tag:theconversation.com,2011:/ca/topics/tunnels-6742/articles
Tunnels – The Conversation
2024-01-08T16:43:06Z
tag:theconversation.com,2011:article/220706
2024-01-08T16:43:06Z
2024-01-08T16:43:06Z
Battle of the Somme: new research shows detonating a massive mine under German lines too early led to a British slaughter
<figure><img src="https://images.theconversation.com/files/568214/original/file-20240108-21-gyo5wk.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C503%2C361&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">'The earth rose in the air to the height of hundreds of feet.': but a delay in the infantry attack meant that hundreds of British troops were killed.</span> </figcaption></figure><p>The <a href="https://youtu.be/xQ_OZfaiUlc?si=xtMTD-H-MGOkRRmu">Battle of the Somme</a> began on July 1 1916 with a spectacular explosion under Hawthorn Ridge – a fortified German frontline position west of the village of Beaumont Hamel in northern France. The footage of the explosion remains one of the best-known <a href="https://www.iwm.org.uk/history/how-the-battle-of-the-somme-was-filmed">pieces of film</a> from the whole conflict.</p>
<p>Almost 60ft below the surface, British miners of the 252 Tunnelling Company had hand dug a gallery for more than 900 metres through chalk and packed it with 40,000lbs of ammonal explosives. It was one of 19 mines placed beneath German front positions that were detonated on July 1 1916, to mark the start of the offensive.</p>
<p>But the mine detonation at Hawthorn Ridge, famously captured by military film director <a href="https://www.iwm.org.uk/history/geoffrey-malins-and-the-battle-of-the-somme-film">Geoffrey Malins</a>, took place ten minutes before the whistles blew at 7.30am. This controversial decision was made in order to protect the attacking British troops from falling debris. </p>
<p>But disastrously, it allowed the Germans to take the crater and repel their advance, leading to massive losses among the attacking British troops from the 29th infantry division.</p>
<p>Malins recorded his feelings <a href="https://www.westernfrontassociation.com/world-war-i-articles/hawthorn-ridge-a-forensic-investigation-into-the-archaeology-and-history-of-hawthorn-crater/">after the event</a> in the film The Battle of the Somme, released later that summer: </p>
<blockquote>
<p>The ground where I stood gave a mighty convulsion, it rocked and swayed … the earth rose in the air to the height of hundreds of feet. Higher and higher it rose, and with a horrible, grinding roar the earth fell back upon itself, leaving in its place a mountain of smoke.</p>
</blockquote>
<h2>Bringing science to bear on history</h2>
<p>Now, the first scientific study to be carried out at the 107-year-old crater has <a href="http://doi.org/10.1080/15740773.2023.2297202">just been published</a> and has unearthed new details on its history. Our team of researchers, which comprised the authors listed here – scientists from Keele and Staffordshire universities supported by a historian from Goldsmiths, University of London – used a range of cutting–edge technology to examine the site as it has never been seen before.</p>
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<figcaption><span class="caption">Drone footage taken over Hawthorn Crater, Beaumont Hamel, Northern France.</span></figcaption>
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<p>Surveys of the surface examined the crater in detail never before seen at this site. It revealed shell holes clustered to the east of the crater that had been created by British artillery in their attempts to dislodge the Germans from their crater stronghold.</p>
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<figcaption><span class="caption">Digital fly-through of ground-based lidar dataset taken at Hawthorn Crater, Beaumont Hamel, Northern France.</span></figcaption>
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<p>Other technical surveys greatly enhanced our knowledge of this internationally significant site. Over two field seasons in 2018 and 2019 we carried out magnetic and electrical resistivity <a href="https://theconversation.com/explainer-how-do-archaeologists-discover-forgotten-ancient-monuments-47317">geophysical surveys</a>, to identify promising areas for subsequent archaeological excavations. </p>
<p>While, due to the variable topographic conditions and the inevitably metallic debris of the battlefield, these surveys were difficult to carry out, they were incredibly valuable, as they pointed the way for fruitful excavations.</p>
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Read more:
<a href="https://theconversation.com/explainer-how-do-archaeologists-discover-forgotten-ancient-monuments-47317">Explainer: how do archaeologists discover forgotten ancient monuments?</a>
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<p>Carried out in the third field season in 2020, these archaeological excavations uncovered hard evidence of the stubborn German defence on that fateful first day on the Somme. Though the early detonation led to the loss of many Württemberg infantrymen of the German 119th Reserve Infantry Regiment, our work uncovered hard evidence of how the newly formed crater was turned to their advantage. </p>
<p>It revealed the still-intact German defensive fire-pits, barbed wire and other materials showing how the Germans quickly built the crater as a new defensive position into their frontline, meaning the chance for the British breakthrough in the early days of the Somme was lost.</p>
<p>An unmanned aerial vehicle (drone) survey – a now common way to <a href="https://theconversation.com/scientists-are-using-drones-to-help-predict-coastal-erosion-60135">map scientific areas of interest</a> – also uncovered evidence of a previously unknown “sap” or shallow tunnel, most probably dug by the Germans after they had captured the crater, probing towards the British lines, again showing their mastery of no man’s land after the initial detonation.</p>
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<figcaption><span class="caption">Footage explaining the conflict archaeology phase of the investigation at Hawthorn Crater, Beaumont Hamel, Northern France.</span></figcaption>
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<h2>If at first you don’t succeed…</h2>
<p>As the battle dragged on towards winter, a second attempt to capture this new position was tried, and this time, was more successful. A second mine was laid using 30,000lbs of ammonal explosive, and was blown from the same tunnel on November 13 1916. </p>
<p>With no delay this time, and with better planning, the mine was much more effective, aiding the 51st Highland Division to capture Hawthorn ridge and the nearby village. </p>
<p>Our surface surveys mapped out this second crater, merging as it does with the original in today’s landscape. This time, archaeological surveys discovered an empty ammunition box for a Vickers machine gun within the crater, reflecting the period of British occupation of the site.</p>
<p>Our study has provided rarely undertaken scientific investigations of a mine crater, and of the strongpoint the Germans built in no man’s land that doomed the initial British attack to failure. </p>
<p>Our results reinforce the notion that blowing the mine ten minutes early was a very bad idea. While it was intended to protect the attackers from falling debris, it gave the Germans time to capture a valuable strongpoint, ripe for fortification. </p>
<p>It was only with concerted effort four months later, and the second mine and subsequent detonation on November 13, that the Hawthorn redoubt was finally captured by the 51st Highlanders, marking the end of the battle some five days later. This time the mine was exploded immediately before the ground assault began – the early detonation of the July 1 was not repeated. </p>
<p>It was a lesson learned the hard way. More than 3 million men fought in the Battle of the Somme, a million of whom were killed or injured, making it one of the deadliest battles in human history.</p><img src="https://counter.theconversation.com/content/220706/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jamie Pringle receives funding from the HLF, the Nuffield Foundation, Royal Society, NERC, EPSRC and EU Horizon2020. He is affiliated with the Geological Society of London. Jamie works for Keele University.</span></em></p><p class="fine-print"><em><span>Kristopher Wisniewski is affiliated with the Geological Society of London.</span></em></p><p class="fine-print"><em><span>Peter Doyle is Secretary of the All Party Parliamentary War Heritage Group, and is Emeritus Professor at London South Bank University</span></em></p><p class="fine-print"><em><span>John Paul Cassella does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>
Thanks to modern geological exploration technology we can piece together the events of July 1 1916 when a tactical error came with massive cost to the British army.
Jamie Pringle, Reader in Forensic Geoscience, Keele University
John Paul Cassella, Lecturer in Forensic Investigation & Analysis, Professor of Forensic Science Education, Atlantic Technological University
Kristopher Wisniewski, Lecturer in Forensic Science, Keele University
Peter Doyle, Professor and Lecturer in Military History, Goldsmiths, University of London
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/218471
2023-11-28T22:34:21Z
2023-11-28T22:34:21Z
Israel’s ground offensive in Gaza City is ignoring the past lessons of urban warfare
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<p>Mediators are seeking to extend the <a href="https://apnews.com/article/israel-hamas-war-news-11-28-2023-a909a0a0c9c76ce80d1ff3e94bbe2ec4">truce between Israel and Hamas</a> beyond Wednesday amid the exchange of hostages for prisoners. But Israeli Prime Minister Benjamin Netanyahu has vowed to <a href="https://www.reuters.com/world/middle-east/hamas-releases-israeli-thai-hostages-under-temporary-truce-2023-11-26/">resume the war with “full force”</a> when the truce ends.</p>
<p>Hamas’s <a href="https://www.bbc.com/news/world-middle-east-67480680">terrorist attack on Oct. 7</a> and Israel’s subsequent aerial bombardment and direct ground operation in Gaza on Oct. 27 have <a href="https://theconversation.com/why-the-israel-gaza-conflict-is-so-hard-to-talk-about-216149">polarized world debate</a>. This has led to a dearth of critical analysis on the conflict. One area where this has been poignantly clear is the lack of attention paid to the tactical problems that Israel’s incursion in Gaza faces.</p>
<h2>The challenges of urban warfare</h2>
<p>Urban warfare is not a new phenomenon. The Iliad, <a href="https://www.gutenberg.org/ebooks/6130">for example</a>, deals with the problems an army encounters in attacking a fortified city. Although much has changed with regards to urban warfare since the Late Bronze Age, one factor has not: urban warfare <a href="https://mwi.westpoint.edu/the-eight-rules-of-urban-warfare-and-why-we-must-work-to-change-them/">favours the defender</a>.</p>
<p>In any military campaign, knowledge of the terrain is of paramount significance. This fact of military operations is even <a href="https://www.researchgate.net/publication/338897778_The_Role_of_Terrain_and_Terrain_Analysis_on_Military_Operations_in_the_Late_Twentieth_to_Early_Twenty-First_Century_A_Case_Study_of_Selected_IDF_Battles">more important</a> in battles against guerrilla forces.</p>
<p>Israel magnified the problem of the urban environment in the immediate aftermath of the Oct. 7 attacks. Since that time, Israel has conducted an <a href="https://ca.news.yahoo.com/news/israels-really-big-bombs-strike-123606995.html">extensive bombing campaign</a> of the Gaza Strip.</p>
<p>Counterintuitively, massive bombardment of urban areas can actually work to a defender’s advantage. International attention, rightfully, is on the <a href="https://www.npr.org/2023/11/11/1212326333/proportionality-israel-gaza-war-war-crimes">number of civilians killed</a> in the bombing campaign. While bombs can be guided with increased confidence that they will hit their target, the destruction that they will create is more uncertain. <a href="https://www.npr.org/2023/11/09/1211571220/israel-gaza-damage-map-satellite-imagery">At least a third</a> of the buildings in Gaza City, if not more, have either been destroyed or damaged.</p>
<p>The debris created by artillery and bombing campaigns aids the defender in two ways. First, debris creates natural choke points and fortifications that the defender can use to control the movement of the aggressor. It can even be to a defender’s advantage <a href="https://mwi.westpoint.edu/defending-the-city-an-overview-of-defensive-tactics-from-the-modern-history-of-urban-warfare/">to intentionally destroy buildings</a> to help funnel attacking forces.</p>
<p>Second, the defender has much more <a href="https://apps.dtic.mil/sti/trecms/pdf/AD1127602.pdf">intimate knowledge</a> of their own city. Unlike an aggressor, which must rely on outside knowledge, the defender knows the city in ways that can only come from firsthand knowledge. The defender, therefore, will know how to bypass the destruction and roadblocks in ways that are impossible for the aggressor.</p>
<h2>Gaza City is not a standard city</h2>
<p>The above issues would be a factor in any urban warfare campaign. Gaza City, however, is not a standard urban environment. Hamas has, in fact, <a href="https://www.reuters.com/world/middle-east/how-hamas-aims-trap-israel-gaza-quagmire-2023-11-03/">prepared the city</a> for precisely the type of operation Israel is now conducting.</p>
<p>The major issue the Israeli military will face in attacking Gaza City is the extensive tunnel network. According to Hamas, the tunnel network is over <a href="https://www.theglobeandmail.com/world/article-gaza-tunnels-israel-hamas/">500 kilometers</a> in length. Israel claims the tunnels are so extensive that they even <a href="https://www.reuters.com/world/middle-east/israeli-army-displays-tunnel-beneath-al-shifa-it-says-served-hamas-hideout-2023-11-22/">extend into</a> the al-Shifa hospital in their attempt to <a href="https://www.aljazeera.com/news/2023/11/15/israels-raid-on-al-shifa-hospital-heres-what-you-should-know">justify their decision to raid</a> it as a viable military target.</p>
<p>The tunnels serve two purposes. First, they enable large segments of Hamas to wait out the bombing campaign. Israel has made the elimination of the tunnels a top priority, using specially <a href="https://www.reuters.com/world/middle-east/with-mapping-robots-blast-gel-israel-wages-war-hamas-tunnels-2023-11-16/">designed munitions, ground forces and robots</a> to map and destroy the tunnels. The scale of the tunnels makes such a task, however, difficult, if not impossible.</p>
<p>Second the tunnels will allow Hamas to deploy its forces in ways that are impossible for the Israeli military. The extensive nature of the tunnels, and the resulting ability of Hamas to move troops and equipment through them, has caused the Israeli military to refer to it as the “<a href="https://crsreports.congress.gov/product/pdf/R/R47754">Gaza Metro</a>.” Much like a metro line, it allows one to bypass clogged streets, in this case caused by the Israeli bombardment, and redeploy elsewhere.</p>
<h2>The call to reserves</h2>
<p>Israel’s military does possess some highly capable units. Israel’s <a href="https://www.msn.com/en-ca/news/world/israeli-air-force-one-of-world-s-most-professional-german-chief-tells-post/ar-AA1jBVuZ">air force</a> and <a href="https://www.businessinsider.com/israel-sends-special-forces-into-gaza-long-war-hamas-2023-10?op=1">special forces</a>, for example, are amongst the most professional and capable in the world. This capability, however, does not extend to the bulk of the Israeli army.</p>
<p>Urban warfare, by its nature, requires a high degree of co-ordination and discipline by the soldiers conducting such operations. This is not the current nature of the Israeli army, at least as <a href="https://www.theatlantic.com/international/archive/2023/10/israeli-military-vulnerable-war-hamas/675591/">constituted for its campaign</a> against the Gaza Strip. Israel, to conduct the operation, had to bolster its army by <a href="https://www.washingtonpost.com/world/2023/10/10/israel-military-draft-reservists/">recalling 360,000 reservists</a> for active duty. </p>
<p>While many of the reservists <a href="https://www.reuters.com/world/middle-east/israels-reservists-drop-everything-rush-home-following-hamas-bloodshed-2023-10-12/">were enthusiastic</a> in their response to the call-up, enthusiasm does not equate with discipline and the ability to co-ordinate with other branches and units.</p>
<p>Problems created by ill-discipline and underpreparedness is exactly what Hamas seeks from Israel at this juncture. Hamas’s leaders <a href="https://www.nytimes.com/2023/11/08/world/middleeast/hamas-israel-gaza-war.html">wanted to bring the Palestinian cause</a> to the forefront of international attention. Actions undertaken by ill-disciplined and undertrained troops will only keep Palestine at the forefront of international attention.</p>
<p>The temporary ceasefire, while hopeful in that it shows <a href="https://www.cnn.com/middleeast/live-news/israel-hamas-war-gaza-news-11-27-23/index.html">negotiation is possible</a> between both sides, does not dramatically alter the urban environment. While Israel may <a href="https://www.aljazeera.com/news/2023/11/21/analysis-how-israel-could-gain-from-a-pause-in-the-gaza-war">replenish the supplies</a> that it expended in the initial bombardment and attack, this does not appreciably change the above constrictions. In fact, it may, for the reasons outlined above, magnify the problems. Given <a href="https://www.cnn.com/2023/10/11/middleeast/maps-population-density-gaza-israel-dg/index.html">Gaza City’s urban density</a> it will be the civilian population, more than Hamas, that suffers.</p><img src="https://counter.theconversation.com/content/218471/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>James Horncastle does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>
Urban warfare and the extensive tunnel network in Gaza benefit Hamas and pose a major challenge to the Israeli military.
James Horncastle, Assistant Professor and Edward and Emily McWhinney Professor in International Relations, Simon Fraser University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/218101
2023-11-20T16:13:27Z
2023-11-20T16:13:27Z
Gaza war: how investigators would go about finding and verifying underground military complexes
<figure><img src="https://images.theconversation.com/files/560242/original/file-20231119-23-wriiqs.png?ixlib=rb-1.1.0&rect=0%2C1%2C1111%2C560&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Computer generated image of an underground bunker released by the Israel Defense Forces.</span> <span class="attribution"><span class="source">IDF/Twitter</span></span></figcaption></figure><p>Following the raid on the al-Shifa hospital in Gaza by units of the Israel Defence Forces on October 15, the IDF claims to have uncovered evidence of tunnels underneath the hospital. A <a href="https://www.youtube.com/watch?v=iY5vNCklg18">video</a> released on November 19 showed a tunnel running under the al-Shifa medical complex at a depth of ten metres, running 55 metres along to what IDF sources said was a blast-proof door.</p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/iY5vNCklg18?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
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<p>The tunnel’s entrance was <a href="https://www.theguardian.com/world/2023/nov/19/idf-israel-army-footage-claims-hamas-tunnel-al-shifa-hospital-gaza">reportedly exposed</a> when a booby-trapped truck in a garage on the hospital’s grounds was exploded. The IDF claims this is evidence that there was a command and control centre beneath the hospital complex.</p>
<p>The video is yet to be independently verified. Given the crucial importance that such evidence will play in justifying a raid on a premises that is protected under the rules of war, such verification will be critical.</p>
<p>There were also claims published several days before the tunnels were reportedly uncovered referencing a 2014 article which asserted that the complex had been <a href="https://twitter.com/huwaidaarraf/status/1724682391988347026?ref_src=twsrc">built in 1983</a> when Israel was in control of Gaza. Again, this claim has not been investigated. Forensic investigation of the site and all records pertaining to construction work there will be of huge importance.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1724682391988347026"}"></div></p>
<p>As forensic investigators, we have extensive experience in below-ground exploration, including <a href="https://theconversation.com/the-science-that-is-helping-researchers-find-the-disappeared-in-latin-america-174600">locating mass graves in Colombia</a>, where – for ethical reasons – it’s not possible to just go in and start digging. So it’s necessary to use a range of technologies above ground to gather sufficient evidence to excavate in what might be a sensitive area. </p>
<p>Every site is unique, but investigators commonly use a phased approach. This may involve initial analysis of <a href="https://www.earthdata.nasa.gov/learn/backgrounders/remote-sensing">remote sensing</a> satellite and aerial data that includes photographs, <a href="http://www.scholarpedia.org/article/Near_infrared_imaging">near-infrared imaging</a> datasets, historical and modern site maps and other available information. Geological maps and subsurface models may be combined with knowledge of the technology and resources available to those excavating tunnels, shafts and chambers. </p>
<p>The <a href="https://www.sciencedirect.com/science/article/abs/pii/S1464343X12001410#:%7E:text=Geology%20of%20the%20Wadi%20Gaza&text=The%20clasts%20are%20mainly%20calcareous,the%20area%20during%20the%20Pleistocene.">terrain under the Gaza Strip</a> comprises rocks and sediments that become thicker from the east of the Red Sea to the Mediterranean. This makes the area suitable for tunnel construction, although there are still hazards in the form of faults that displace layers of rock and allow water to get into underground spaces (especially close to the sea).</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/560240/original/file-20231119-17-7npwo6.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Map of tunnels uncovered by Israeli Defense Forces after Operation Protective Edge in 2014." src="https://images.theconversation.com/files/560240/original/file-20231119-17-7npwo6.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/560240/original/file-20231119-17-7npwo6.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=517&fit=crop&dpr=1 600w, https://images.theconversation.com/files/560240/original/file-20231119-17-7npwo6.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=517&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/560240/original/file-20231119-17-7npwo6.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=517&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/560240/original/file-20231119-17-7npwo6.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=650&fit=crop&dpr=1 754w, https://images.theconversation.com/files/560240/original/file-20231119-17-7npwo6.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=650&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/560240/original/file-20231119-17-7npwo6.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=650&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Map of tunnels uncovered by Israel Defence Forces after Operation Protective Edge in 2014.</span>
<span class="attribution"><span class="source">Israeli Defense Forces/Jewish Virtual Library</span></span>
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</figure>
<h2>Hi-tech tunnel hunters</h2>
<p>This pattern of surface and deep geology would then identify areas for <a href="https://en.wikipedia.org/wiki/Near-surface_geophysics">near-surface geophysics</a> site surveys that may use active technology to <a href="https://www.keyence.com/ss/products/daq/lab/pulse/base.jsp#">pulse signals</a> and measure the responses before mechanical drilling or excavation to identify areas or objects of interest. Even relatively deep targets such as <a href="http://doi.org/10.3997/1873-0604.2011028">mineshafts</a> and <a href="https://theconversation.com/how-to-detect-a-sinkhole-before-it-swallows-you-up-101543">sinkholes</a> have been located using this approach.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1718010359397634252"}"></div></p>
<p>Specialised seismic and <a href="https://geotecsurveys.com/gpr-surveys-underground?gclid=Cj0KCQiApOyqBhDlARIsAGfnyMqYLZ00WH-ZB1bkXr-3qymO01j5b3_TAWFUSC9qCUuSxK5zxAWBK_UaAos1EALw_wcB">ground penetrating radar</a> (GPR) geophysical surveys <a href="https://theconversation.com/in-gaza-the-underground-war-between-israeli-troops-and-hamas-fighters-in-the-tunnels-is-set-to-begin-217032">have been used to detect</a> tunnels in Gaza. But this gets progressively more difficult the deeper they are – some in the Gaza Strip are reportedly as <a href="https://theconversation.com/what-the-israel-defence-forces-can-expect-when-they-enter-the-gaza-metro-tunnel-system-216767">deep as 70m</a>. </p>
<p>To detect tunnels and bunkers below human-made structures, <a href="https://en.wikipedia.org/wiki/Remote_sensing">remote sensing methods</a> commonly use instruments on satellites, unmanned aerial vehicles and aircraft to provide datasets to analyse. Once interpreted, these can pick up disturbed versus undisturbed soil and pinpoint areas of high gases such as methane or heat emitters. But these would have to be very sensitive and interpretation is typically very difficult for deeply buried targets. Entrances would be key to locate here – that is apparently the case in the al-Shifa hospital. </p>
<p><a href="https://www.keele.ac.uk/geophysics/microgravity/applications/">Micro-gravity methods</a> that could detect missing mass, such as tunnels and bunkers, have been used within buildings. They have been used, for example, to detect <a href="https://doi.org/10.3997/1873-0604.2012034">burial sites below church floors</a> and <a href="https://doi.org/10.1007/s00024-022-03010-2">Egyptian pyramid tombs</a> as this technique is not depth limited. Airborne <a href="https://geodesy.noaa.gov/GEOID/GSVS/gravity.shtml">gravity gradient surveys</a>, that use what is called <a href="http://www.geolithe.uk/microgravimetry/">microgravitmetry</a> to detect targets, show potential, but may not have the required resolution to detect bunkers at such depths in this case.</p>
<p>Both the microgravity surveys, data processing and numerical modelling are used to calibrate results to estimate what is causing the data signal. It’s then important to accurately digitally remove the effect of the above-ground extra mass of buildings to then look at what’s underneath. The cost of this can be significant in terms of time and resources. </p>
<p>In the past, high-resolution GPR surveys have detected <a href="http://doi.org/10.3997/1873-0604.2008042">unmarked cellars</a> beneath commercial shop floors and <a href="http://doi.org/10.1016/j.forsciint.2013.12.036">hidden pipebombs and detonators</a> behind shower tiles in Northern Ireland. But GPR is depth-limited to a few metres in most cases, with metal reinforcements causing problems in the data. </p>
<h2>Listen up</h2>
<p>An alternative approach is possibly the oldest: listening for sounds from underground. From <a href="https://en.wikipedia.org/wiki/Tunnelling_companies_of_the_Royal_Engineers">listening to tunnels being dug</a> (as they did on the western front during the first world war), or detecting vibrational energy from sound sources, most especially sound produced from tunnels being dug or by people themselves, walking, talking and making noise. </p>
<p>This too has severe constraints. You are effectively “listening” to what is going on under sometimes metres of ground – the vibrations – and it’s often difficult to tell the difference between the sound of low-energy seismic movements and human-made sources. It also takes time to process and potentially model the data too.</p>
<p>There are a range of <a href="https://www.gov.uk/government/publications/land-contamination-risk-management-lcrm/lcrm-stage-1-risk-assessment#intrusive-site-investigation">intrusive investigation techniques</a>. These include sinking slim borehole systems and inspection cameras on cables. But they are slower digging methods – particularly when they involve drilling through bedrock and reinforced concrete.</p>
<p>The final stage is visual inspection. Verifying the function of the tunnel, shaft or chamber requires examination of the equipment contained there. Judgments have also got to be made about whether the structure was physically able to be used for a military purpose – whether that’s the storage of weapons, as a bunker for troops to hide or for a full-blown command and control centre with all the equipment, power sources and connectivity that would require.</p>
<p>The only true way to be definitive about the presence of subsurface structures in Gaza is by physical investigation, which will take significant time and effort, especially with the reported depths below ground level involved.</p><img src="https://counter.theconversation.com/content/218101/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jamie Pringle receives funding from the HLF, the Nuffield Foundation, Royal Society, NERC, EPSRC and EU Horizon2020. He is affiliated with the Geological Society of London. Jamie works for Keele University.</span></em></p><p class="fine-print"><em><span>Alastair Ruffell receives funding from RCUK (NERC and EPSRC). He is affiliated with the Queen's University, Belfast, the Geological Society of London and International Union of Geosciences</span></em></p>
Israel claims to have found a Hamas underground command and control system in the al-Shifa medical complex.
Jamie Pringle, Reader in Forensic Geoscience, Keele University
Alastair Ruffell, Reader, Queen's University Belfast
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/216830
2023-11-08T23:08:26Z
2023-11-08T23:08:26Z
Hidden tunnels, ambushes and explosives in walls: the Israel-Hamas war enters a precarious new phase
<p>With Israeli Defence Forces now reportedly surrounding Gaza City, the most densely packed part of the Gaza Strip, their fight against Hamas has entered a new phase focused primarily on urban warfare – some of it underground.</p>
<p>Sappers are the soldiers who clear paths through obstacles with machines and explosives, enabling other troops to overwhelm the enemy. They also create such obstructions and lay traps and mines when trying to defend a position. </p>
<p>Tunnels are a sapper’s job, too. Indeed, this is where the word comes from: the ancient technique of “sapping” beneath the surface to approach an enemy position protected from their arrows, bullets or shells.</p>
<p>As part of their <a href="https://mwi.usma.edu/defending-the-city-an-overview-of-defensive-tactics-from-the-modern-history-of-urban-warfare/">plan</a> for defence, Hamas sappers have excavated a huge series of <a href="https://mwi.westpoint.edu/underground-nightmare-hamas-tunnels-and-the-wicked-problem-facing-the-idf/">tactical tunnels</a>. Some are interlinked, some isolated. Some have been dug far below where bombs can reach, some are near the surface to allow access. </p>
<p>Tunnels and “mouseholes” in walls also allow for undetected movement between buildings. <a href="https://www.ft.com/content/913d366e-0ace-4463-a004-d293aa49c673">Hamas fighters expect</a> they can emerge from these holes to attack Israeli soldiers before disappearing again. </p>
<p>In addition, Hamas sappers have likely prepared many improvised explosive devices (IEDs) – some hidden in walls to detonate when <a href="https://cat-uxo.com/explosive-hazards/ied/explosively-formed-projectile-efp">armoured vehicles pass by</a> and other, larger explosives buried under roads. </p>
<p>Some tunnels may also be set as traps to entice Israeli soldiers to enter as they search for hostages.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1720248174823063648"}"></div></p>
<h2>Urban warfare is excruciatingly slow</h2>
<p>As the war enters a new phase, it is pitting a grimly determined Israeli Defence Force (IDF), with the world’s <a href="https://www.timesofisrael.com/mini-gaza-the-idfs-urban-warfare-training-center-a-town-thats-known-only-war/">best</a> capabilities for urban warfare, against a force ready for martyrdom that has prepared for this fight for years. It will also be happening on terrain that analysts <a href="https://mwi.usma.edu/city-not-neutral-urban-warfare-hard/">argue</a> greatly favours the defender.</p>
<p>Though fighting in Gaza presents its own unique challenges, there are some lessons to be learned from the operations to eliminate Islamist fighters from the Iraqi city of Mosul and the southern Philippines city of Marawi in 2016-17. </p>
<p>In <a href="https://mwi.westpoint.edu/urban-warfare-project-case-study-2-battle-of-mosul/">Mosul</a>, a US-supported Iraqi force of about 100,000 took nine months to destroy an ISIS force of thousands in a thoroughly fortified city. The coalition lost <a href="https://www.ft.com/content/32bc687b-1385-401b-a60a-7320848ceb16">8,000 troops</a> and many tanks and <a href="https://www.washingtonpost.com/world/middle_east/bulldozers-have-become-more-crucial--and-more-vulnerable--in-the-fight-against-the-islamic-state/2017/05/29/0e6caf3a-409a-11e7-b29f-f40ffced2ddb_story.html">bulldozers</a> to massive IEDs. </p>
<p>Progress was equally slow in <a href="https://www.aspi.org.au/report/marawi-crisis-urban-conflict-and-information-operations">Marawi</a>, where it took five months for Filipino forces to defeat ISIS-Maute fighters. Troops could sometimes secure only one building per day because of the constant threat of ambush from tunnels and IEDs hidden in entrances, windows and stairwells.</p>
<h2>Three layers of challenges</h2>
<p>Urban war presents armies with compounding challenges. </p>
<p>The <a href="https://groundedcuriosity.com/unpacking-the-urban-fight-introducing-the-twelve-challenges-part-i-of-a-series/">first layer</a> is perceptual. There is a cognitive dissonance between a liberal society’s beliefs around the need for restraint in conflict and the primordial demands of urban war with its high costs in blood, destruction and legitimacy. Armies are averse to preparing for such horror. </p>
<p>Second, there are tactical challenges with fighting among buildings: </p>
<ul>
<li><p>the threat of remote attack by drones or IEDs </p></li>
<li><p>the uncertainty created by hidden adversaries </p></li>
<li><p>the extreme exposure of forces as they advance</p></li>
<li><p>the dilution of combat power as forces are channelled, isolated and dispersed among buildings, with very restricted views</p></li>
<li><p>the degrading of sensors and communications systems. </p></li>
</ul>
<p>Third, and critically, the <a href="https://www.icrc.org/en/what-we-do/war-in-cities">presence of civilians</a> in urban war zones imposes moral and ethical challenges. They suffer <a href="https://www.icrc.org/en/document/new-research-shows-urban-warfare-eight-times-more-deadly-civilians-syria-iraq">disproportionately and catastrophically</a>, both as immediate casualties and from displacement and disease following the destruction of cities. </p>
<p>Military commanders also face a proportionality <a href="https://www.e-ir.info/2022/05/27/the-lawful-killing-of-civilians-under-international-humanitarian-law/">dilemma</a> when it comes to <a href="https://www.justsecurity.org/56087/ambiguity-conduct-hostilities/">interpreting</a> international humanitarian law. They need to balance the necessity of their actions and the survival of soldiers against causing unintended but foreseeable civilian harm.</p>
<p>Further complexities include:</p>
<ul>
<li><p>the obligation of forces to provide security and logistical support to noncombatants</p></li>
<li><p>the security threat from phone and social media usage by civilians</p></li>
<li><p>civilians who are hostile, obstructive or offer unarmed resistance</p></li>
<li><p>the psychological and political burden on commanders that may distort their decision-making. </p></li>
</ul>
<h2>How Israel has been preparing for this moment</h2>
<p>The IDF has previously experienced these challenges in Gaza. After Israeli occupation ended in 2005, militant attacks prompted major incursions by the army in 2008 and 2014. That fighting taught the IDF key <a href="https://www.rand.org/content/dam/rand/pubs/research_briefs/RB9900/RB9975/RAND_RB9975.pdf">lessons</a>. </p>
<p>From a political standpoint, Israel realised the importance of winning the contest of international and domestic public opinion. From a military and operational standpoint, the IDF learned that precision air power alone could not eliminate the threat from Hamas. Well-protected armoured vehicles were essential, and new capabilities were needed to counter the increasing use of tunnels by Hamas. </p>
<p>As a result, the IDF is uniquely well-equipped for urban operations, with the world’s best-protected tanks and <a href="https://www.forbes.com/sites/davidaxe/2023/10/13/israels-namer-is-the-heaviest-best-protected-armored-personnel-carrier-in-the-world-hamas-just-captured-one/?sh=1585941a5271">armoured personnel carriers</a>. </p>
<p>It also has world-leading armoured engineering vehicles, such as the <a href="https://www.armyrecognition.com/defense_news_july_2023_global_security_army_industry/israel_defense_force_uses_armored_caterpillar_d9_bulldozers_to_destroy_ieds_in_palestinan_camp_of_jenin.html">D9 armoured “Doobi” bulldozer</a>. With the D9, houses can be demolished instead of entered, reducing the risk of ambush and IEDs. However, these bulldozers have been controversially associated with destroying homes as punishment. </p>
<p>The D9 will be used in the war to create safe paths through terrain that may be mined, push alternative routes through buildings and build protective berms around “secured areas” to consolidate the IDF’s progress. Some of these bulldozers can even be operated by remote control.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/558224/original/file-20231108-29-lujaxp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/558224/original/file-20231108-29-lujaxp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=463&fit=crop&dpr=1 600w, https://images.theconversation.com/files/558224/original/file-20231108-29-lujaxp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=463&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/558224/original/file-20231108-29-lujaxp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=463&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/558224/original/file-20231108-29-lujaxp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=582&fit=crop&dpr=1 754w, https://images.theconversation.com/files/558224/original/file-20231108-29-lujaxp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=582&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/558224/original/file-20231108-29-lujaxp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=582&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The IDF’s Caterpillar D9R armoured bulldozer.</span>
<span class="attribution"><span class="source">Zachi Evenor/Wikimedia Commons</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Other armoured engineering vehicles include the <a href="https://www.militarytoday.com/engineering/puma.htm">Puma minefield breacher</a>, with the <a href="https://www.rafael.co.il/wp-content/uploads/2019/03/Carpet.pdf">Carpet</a> mine and IED clearing system that can detonate or disrupt hidden munitions with blasts from
fuel-air explosive rockets. Engineer vehicles also carry equipment that can jam IED circuits or transmissions. Some may also have the <a href="https://www.ynetnews.com/articles/0,7340,L-5170565,00.html#:%7E:text=The%20IDF%20chose%20to%20make%20relatively%20rare%20use,the%20border%20of%20the%20Gaza%20Strip%20last%20December.">THOR</a> system, which uses lasers to explode IEDs.</p>
<p>Soldiers are also trained to find, operate in and destroy tunnels. They include elements of the <a href="https://www.idf.il/en/mini-sites/the-hamas-terrorist-organization/this-is-the-idf-s-plan-to-combat-hamas-terror-tunnels/">Sarayet Yahalom</a>, a special forces unit that uses specialised demolition charges, subterranean drones and robots. </p>
<p>The Israelis lead the world in highly classified <a href="https://www.israelandstuff.com/israeli-team-who-developed-terror-tunnel-detection-system-wins-defense-prize">subterranean sensing research</a>, including the use of geospatial, acoustic, seismic, electrical resistivity tomography (ERT) and ground-penetrating radar technologies. The IDF’s public statements suggest tunnels within 20 metres of the surface can be mapped. </p>
<p>The IDF tunnel sappers also have <a href="https://aw.my.games/en/news/general/heavy-apcs-centurion-variants">niche armoured fighting vehicles</a>. Some are fitted with the technologies mentioned above, others with drilling equipment that can bore down into tunnels to deliver devices, materials or explosives. One, the Nakpilon, uniquely has a door at the front to deploy soldiers straight into tunnel entrances. </p>
<p>The IDF has generally preferred to destroy tunnels from the surface rather than entering, but some Yahalom and other <a href="https://www.isayeret.com/">reconnaissance special forces</a> train to fight below ground, alongside the Oketz dog unit, with specialised vision, breathing and communications equipment. </p>
<p>Given the scale of the tunnel network and the task of recovering hostages, some human reconnaissance seems unavoidable. <a href="https://historycollection.com/10-crazy-things-never-knew-tunnel-rat-soldiers-vietnam-war/3/">History suggests</a> this will be done by pairs or individuals, perhaps the <a href="https://www.jewishvirtuallibrary.org/the-mista-arvim">Mista’arvim elite undercover units</a>, who may operate by disguising themselves as Hamas fighters. </p>
<p>Given the Hamas advantage of home terrain and the advanced technology deployed by Israel, both sides will likely inflict bloody surprises on one another. The IDF has the military capability to prevail, but the human cost of the ground war and the outcome of the crucial geopolitical war of narratives remain unclear.</p><img src="https://counter.theconversation.com/content/216830/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Charles Knight does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>
Though Hamas has the advantage of fighting on its territory, Israel has developed one of the most effective urban fighting militaries in the world.
Charles Knight, Adjunct Lecturer in Terrorism and Assymetric Conflict and Senior Researcher in Urban Warfare (UNSW), Charles Sturt University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/217032
2023-11-08T13:38:26Z
2023-11-08T13:38:26Z
In Gaza, the underground war between Israeli troops and Hamas fighters in the tunnels is set to begin
<figure><img src="https://images.theconversation.com/files/558070/original/file-20231107-252596-7d74iu.jpg?ixlib=rb-1.1.0&rect=48%2C48%2C4537%2C3320&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A Hamas fighter steps out of a tunnel during a 2014 public demonstration of the group's military abilities.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/fighter-from-izz-al-din-al-qassam-stands-in-front-of-a-news-photo/1546737195">Yousef Masoud/SOPA Images/LightRocket via Getty Images</a></span></figcaption></figure><p>The Israel Defense Forces have announced that they have <a href="https://www.usatoday.com/story/news/world/israel-hamas/2023/11/01/israel-hamas-gaza-war-live-updates/71405089007/">reached the outskirts of Gaza City</a> and are <a href="https://www.latimes.com/world-nation/story/2023-11-06/israeli-forces-cuts-off-north-gaza">expecting to enter the city soon</a>. </p>
<p>When that happens, Israeli troops will begin a dangerous new phase of the military campaign against Hamas fighters in a densely populated urban terrain that includes closely packed buildings above ground and a troubling maze of tunnels below.</p>
<p>Until now, Israel’s campaign against Hamas seems to have been primarily carried out from the air, including via laser-guided <a href="https://www.bbc.com/news/world-middle-east-67097124">bunker-buster bombs</a>, which are armed with deep-penetrating warheads and delayed fuses to enable them to blow up underground.</p>
<p>But on Oct. 29, 2023, the Israel Defense Forces said its troops had <a href="https://news.sky.com/story/israel-says-it-has-attacked-gunmen-inside-hamas-tunnels-and-releases-video-from-gaza-12997068">attacked Hamas gunmen in a tunnel</a> and killed <a href="https://www.timesofisrael.com/firefights-as-idf-troops-clash-with-gunmen-in-gaza-and-rockets-pound-central-israel/">Hamas fighters who emerged from a tunnel</a> to attack their positions in northwest Gaza. </p>
<p>Hamas subsequently posted a video of what <a href="https://news.sky.com/story/israel-says-it-has-attacked-gunmen-inside-hamas-tunnels-and-releases-video-from-gaza-12997068">appears to be the same attack</a> from the perspective of one of its fighters, moving across a sandy beach to strike the Israelis. </p>
<p>And on Nov. 5, 2023, Israel reported that three Hamas fighters <a href="https://www.nbcnews.com/news/world/israel-gaza-hamas-tunnels-fighters-war-rcna123708">emerged from a hidden tunnel and ambushed Israeli troops</a> behind what its forces had thought were the front lines.</p>
<p>I studied tunnel warfare during my <a href="https://www.brianglynwilliams.com/iraqi_kurdistan/field_iraqi_kurdistan.html">fieldwork in Iraq</a>, where the Islamic State group created a vast underground tunnel fortress in their defense of the city of Mosul. And I have analyzed the Germans’ underground tunnel and sewer “<a href="https://historynewsnetwork.org/article/182854">rattenkrieg</a>,” or “rat war,” fought to defeat the Soviets in one of the largest urban battles in history, the <a href="https://www.iwm.org.uk/history/what-you-need-to-know-about-the-battle-of-stalingrad">1942-43 Battle of Stalingrad</a>. </p>
<p>These and other historic battles teach one important lesson: Tunnel warfare tends to lessen many advantages a stronger, more advanced attacker might otherwise expect – and to favor the defenders hidden underground.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/558073/original/file-20231107-252894-heb81a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Men in camouflage uniforms look at a massive hole in the ground." src="https://images.theconversation.com/files/558073/original/file-20231107-252894-heb81a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/558073/original/file-20231107-252894-heb81a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/558073/original/file-20231107-252894-heb81a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/558073/original/file-20231107-252894-heb81a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/558073/original/file-20231107-252894-heb81a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/558073/original/file-20231107-252894-heb81a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/558073/original/file-20231107-252894-heb81a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Palestinian security forces examine a tunnel from the Gaza Strip into Israel that was destroyed by an Israeli airstrike in 2017.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/palestinian-security-forces-loyal-to-hamas-stand-at-the-news-photo/993035036">Hatem Omar/picture alliance via Getty Images</a></span>
</figcaption>
</figure>
<h2>Hamas plans a trap below ground</h2>
<p>From news reports, researchers and both Israeli and Hamas sources, it seems clear that Hamas has systematically built a complex underground city fortified with strong defenses beneath Gaza.</p>
<p>Yehia Sinwar, Hamas’ political leader, has claimed that the militant group has dug <a href="https://www.nbcnews.com/news/world/israeli-soldiers-will-face-labyrinth-hamas-tunnels-rcna121459">310 miles (500 kilometers) of tunnels</a> under the Gaza Strip. Hostages from this war and past ones have <a href="https://www.washingtonpost.com/world/2023/10/24/israel-hamas-hostage-released-testimony/">offered eyewitness accounts of being held in this vast underground tunnel complex</a>. </p>
<p>The Israeli military has a website dedicated to what it calls “the underground city of terror,” in which it claims Hamas has built the concrete-reinforced passageways with construction materials <a href="https://www.idf.il/en/mini-sites/the-hamas-terrorist-organization/everything-you-need-to-know-about-hamas-underground-city-of-terror/">stolen from international donations</a> meant to aid the people of Gaza. The United Nations has alleged Hamas has stolen various humanitarian supplies, but it has also <a href="https://www.timesofisrael.com/un-refugee-agency-says-hamas-stole-fuel-and-medications-from-its-gaza-premises/">walked back those allegations</a>.</p>
<p>Israel says many of the entrances to the tunnels are “<a href="https://www.idf.il/en/mini-sites/the-hamas-terrorist-organization/everything-you-need-to-know-about-hamas-underground-city-of-terror/">hidden between schools, mosques, hospitals and other civilian buildings</a>.” In 2014, Israeli forces even reported finding a tunnel entrance hidden in a <a href="https://www.idf.il/en/mini-sites/ground-forces/combat-engineering-corps/diamonds-in-the-rough-finding-weapons-nobody-else-can/">washing machine in a Palestinian home</a>.</p>
<p>Hamas fighters have reportedly <a href="https://www.cnn.com/2023/10/28/middleeast/hamas-tunnels-gaza-intl/index.html">lined the tunnels with transport rails</a> to move rockets to locations where they can be launched from firing pads concealed by trap doors. Hamas’ tunnelers have also apparently built <a href="https://www.npr.org/2023/11/01/1210000788/a-look-at-hamas-labyrinthine-tunnel-network">sleeping areas</a>, ventilation and resupply shafts, medical facilities and command centers. There are also storage areas said to hold food for a siege, fuel, weapons and ammunition – and even areas to <a href="https://www.washingtonpost.com/world/2023/11/03/gaza-tunnels-hamas-israel-war/">manufacture rockets</a>. This advanced tunnel network is all reportedly interconnected by a <a href="https://www.cnn.com/2023/10/24/politics/intelligence-hamas-israel-attack-tunnels-phone-lines/index.html">wired telephone system</a>, and guarded by <a href="https://www.smh.com.au/world/middle-east/booby-traps-mines-hamas-tunnel-network-under-gaza-helps-in-a-war-20231013-p5ec5o.html">mines and booby traps</a>.</p>
<p>Even if only some of those claims are true, it is clear that Hamas has built a formidable subterranean fortress beneath Gaza City that is <a href="https://www.reuters.com/world/middle-east/how-hamas-secretly-built-mini-army-fight-israel-2023-10-13">meant to be a trap for the Israelis</a> as well as a refuge for Hamas.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/558074/original/file-20231107-27-edfclt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A person walks through a concrete tunnel." src="https://images.theconversation.com/files/558074/original/file-20231107-27-edfclt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/558074/original/file-20231107-27-edfclt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/558074/original/file-20231107-27-edfclt.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/558074/original/file-20231107-27-edfclt.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/558074/original/file-20231107-27-edfclt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/558074/original/file-20231107-27-edfclt.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/558074/original/file-20231107-27-edfclt.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A Palestinian youth walks inside a tunnel used for military exercises during a weapons exhibition at a Hamas-run youth summer camp in Gaza City on July 20, 2016.</span>
<span class="attribution"><a class="source" href="https://newsroom.ap.org/detail/IsraelPalestiniansHamasTunnels/430337b57c1a463e889d815a407cb595/photo">AP Photo/Adel Hana</a></span>
</figcaption>
</figure>
<h2>Israel’s plans to defeat the tunnel fortress</h2>
<p>Israeli forces have encountered these tunnels before.</p>
<p>In 2013, for example, <a href="https://www.rand.org/pubs/research_briefs/RB9975.html">Israeli troops unearthed a particularly large invasion tunnel</a> that began nearly three-quarters of a mile (1 km) inside the Gaza border, and was 72 feet (22 meters) deep. It burrowed under the border wall and was detected nearly 60 feet (18 meters) below the surface 1,000 feet (300 meters) inside Israel. </p>
<p>In 2014, Israeli troops fought underground during a <a href="https://merip.org/2015/10/operation-protective-edge">51-day ground invasion of Gaza</a> waged to destroy some of the tunnels. During that campaign, <a href="https://www.rand.org/pubs/research_briefs/RB9975.html">Israeli troops were surprised by the requirements of tunnel warfare</a>, according to an analysis by the Rand Corporation think tank. They <a href="https://www.rand.org/pubs/research_briefs/RB9975.html">had trouble finding</a>, fighting in and destroying what they came to call the “<a href="https://www.npr.org/2023/11/02/1210088853/one-of-israel-s-military-challenges-in-gaza-is-dealing-with-hamas-network-of-tun">Gaza metro</a>.” </p>
<p>Since that experience, Israel has created a <a href="https://www.npr.org/2023/11/02/1210088853/one-of-israel-s-military-challenges-in-gaza-is-dealing-with-hamas-network-of-tun">special tunnel-warfare unit</a>, known as Samur, which translates as “weasels” in Hebrew, that is trained specifically to fight underground. </p>
<p>The Samur unit has been working for years to develop sensors that can <a href="https://www.timesofisrael.com/new-technology-to-help-idf-locate-tunnels-in-gaza/">detect underground tunnels</a>, booby traps and explosives. </p>
<p>The troops have also developed ground-penetrating radar <a href="https://www.thenationalnews.com/mena/palestine-israel/2023/10/31/robots-and-attack-dogs-what-israel-brings-to-tunnel-combat/">to identify tunnels</a>. </p>
<p>And when they find a tunnel, they can destroy or seal its entrance with specialized weapons known as “<a href="https://www.telegraph.co.uk/world-news/2023/10/25/sponge-bomb-new-weapon-israel-gaza-tunnels-war-hamas/">sponge bombs</a>.” These have no explosives but instead contain quickly expanding foam that hardens like concrete to seal off passages.</p>
<p>The Samur unit also has specially trained military dogs that can <a href="https://www.thenationalnews.com/mena/palestine-israel/2023/10/31/robots-and-attack-dogs-what-israel-brings-to-tunnel-combat/">detect explosives in the tunnels</a> and attack opposing troops.</p>
<p>The tunnel corps troops are taught to operate <a href="https://www.thenationalnews.com/mena/palestine-israel/2023/10/31/robots-and-attack-dogs-what-israel-brings-to-tunnel-combat/">mobile robots equipped with cameras</a> that can explore tunnels, relay pictures back and detonate booby traps without risking human lives.</p>
<p>Those who are chosen for this unit are reportedly soldiers who can <a href="https://www.cnn.com/2023/10/30/opinions/hamas-underground-tunnels-richemond-barak-bergen/index.html">tolerate the tunnels’ oppressive environment</a>. Conditions in the underground passages are said to be “<a href="https://www.timesofisrael.com/like-fighting-ghosts-the-challenge-the-idf-faces-in-destroying-hamass-tunnels/">dark, terrifying and claustrophobic</a>,” with “ghosts” coming out of the darkness to attack.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/bzY59lJ1A-w?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">In 2014, Vice News got a rare view of Israeli forces training for urban combat at a facility designed to look like Gaza City.</span></figcaption>
</figure>
<p>Israel’s troops train for urban combat, including in tunnels, at a <a href="https://www.dw.com/en/how-israel-is-training-for-urban-warfare/a-67134424">mock-up Palestinian city</a> on a military base located in the Negev Desert. They also use <a href="https://www.cnn.com/2023/10/28/middleeast/hamas-tunnels-gaza-intl/index.html">virtual reality environments</a> built from digital scans of actual tunnels discovered in previous military operations to train their troops for subterranean warfare.</p>
<p>According to <a href="https://crsreports.congress.gov/product/pdf/R/R47754#page=40">an Oct. 20, 2023, Congressional Research Service report</a>, it is likely that some of these facilities and technologies were paid for by American taxpayers, as part of US$320 million in U.S. military funding meant for U.S.-Israel collaboration on “detecting, mapping, and neutralizing underground tunnels that threaten either country.”</p>
<p>But all this practice and preparation may not be enough. Harel Chorev, a Palestinian historian at Tel Aviv University’s Moshe Dayan Center for Middle Eastern and African Studies, has said, “<a href="https://www.cnbc.com/2023/10/12/israel-hamas-war-gaza-tunnels-pose-deadly-challenge.html">Nobody really knows what’s underground</a>. I don’t see Israeli soldiers being able to storm these tunnels.” </p>
<p>But as Israeli troops prepare to plunge into the densely packed heart of Gaza City in an effort to occupy the city above ground, they will likely end up fighting in a dangerous city below ground, too.</p><img src="https://counter.theconversation.com/content/217032/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Brian Glyn Williams does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>
Tunnel warfare tends to lessen any advantages a stronger, more advanced attacker might otherwise expect – and to favor the defenders hidden underground.
Brian Glyn Williams, Professor of Islamic History, UMass Dartmouth
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/216767
2023-11-01T14:01:57Z
2023-11-01T14:01:57Z
What the Israel Defence Forces can expect when they enter the ‘Gaza Metro’ tunnel system
<p>Amid fears of yet another long war in the region, Israel has now begun its ground campaign in Gaza. The Israel Defence Forces (IDF) has already claimed several successes in its three-week campaign, including the elimination of several terrorist leaders <a href="https://www.reuters.com/world/middle-east/hamas-says-it-fires-israeli-troops-pressing-gaza-ground-assault-2023-10-31/">including Ibrahim Biari</a>, who it described as a “ringleader” of the October 7 attacks, and <a href="https://www.reuters.com/world/middle-east/israeli-soldier-freed-gaza-during-ground-operation-israeli-army-says-2023-10-30/">liberating at least one hostage</a> held by Hamas.</p>
<p>But Israel’s military commanders will know that this is unlikely to be a simple operation. Among the factors complicating their mission of eliminating Hamas is the “<a href="https://www.cbsnews.com/news/israel-hamas-war-news-targets-tunnel-network-gaza-next-phase/">Gaza Metro</a>”, a vast network of interconnected tunnels within the region. Having invested heavily in subterranean infrastructure over the years, Hamas is counting on this network to aid its survival in the coming weeks.</p>
<p>Underground engineering has a long history in warfare. From <a href="https://link.springer.com/chapter/10.1007/978-1-4020-3105-2_3">antiquity to Vietnam</a>, a range of groups have used tunnels to gain an advantage. </p>
<p>Not only can they provide <a href="https://mwi.westpoint.edu/elephant-tunnel-preparing-fight-win-underground/">concealment and freedom of movement</a>, but they also present a range of challenges for the attacking force – they can be hardened against any attacks from the surface. Storming underground networks can also be prohibitively difficult for an attacker, given the limited space available.</p>
<p>Sometimes they work. Sometimes they don’t. For instance, the threat posed by western airpower caused Islamic State (IS) to construct a <a href="https://www.washingtonpost.com/news/worldviews/wp/2017/04/14/the-islamic-state-has-tunnels-everywhere-its-making-them-much-harder-to-defeat/">large network of tunnels</a>. These tunnels made <a href="https://www.opendemocracy.net/en/north-africa-west-asia/tunnel-warfare-the-islamic-states-subterranean-war/">surveillance and airstrikes difficult</a> and were riddled with traps, making capture by ground forces dangerous and difficult. </p>
<p>These benefits only really work if the tunnels are defended, of course, which wasn’t always the case. For instance, in the 2015 battle for Sinjar, <a href="https://info.publicintelligence.net/USArmy-BattleforSinjar.pdf">the majority of IS fighters were long gone</a> by the time Kurdish land forces arrived to liberate the city.</p>
<h2>Established network</h2>
<p>Hamas’s tunnel network presents a unique problem for the IDF. There have been tunnel networks in Gaza for years. Initially used <a href="https://www.jstor.org/stable/10.1525/jps.2012.xli.4.6">for smuggling</a>, they were quickly turned towards offensive uses, playing a role in <a href="https://www.inss.org.il/he/wp-content/uploads/sites/2/systemfiles/SystemFiles/Subterranean%20Warfare_%20A%20New-Old%20Challenge.pdf">kidnapping and weapons storage</a>. </p>
<p>The Hamas subterranean networks really began to evolve after 2012, when restrictions were lifted on the importing of <a href="https://www.aljazeera.com/news/2012/12/30/israel-eases-ban-on-gaza-building-material">building materials</a> to the region. The militant group was able to <a href="https://www.jpost.com/operation-protective-edge/exclusive-us-intelligence-source-claims-hamas-has-many-more-tunnels-than-israel-says-368364">redirect construction supplies</a> away from civilian infrastructure projects to expand its underground presence. </p>
<p>While the tunnels <a href="https://www.tandfonline.com/doi/pdf/10.1080/14650045.2017.1399878">vary in quality</a>, many are well equipped and hardened, and deep enough to evade detection by ground penetrating radar.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1719370808408113525"}"></div></p>
<p>Unsurprisingly, key Hamas allies, <a href="https://www.iranintl.com/en/202310301314">including Iran</a> are boasting about the Gaza Metro. The network provides the group with a haven and a means to move around the region unobserved. </p>
<p>It places leadership and organisational infrastructure out of reach from air attacks. The system is <a href="https://www.nytimes.com/2023/10/27/world/middleeast/palestine-gazans-hamas-food.html">laden with supplies</a> as well as weapons and fuel. </p>
<p>Defended, booby-trapped and likely to be populated with <a href="https://www.nytimes.com/article/israel-hostages-hamas-explained.html">human shields and hostages</a> as well as fighters, they will be challenging for even a well-equipped and capable attacking force. </p>
<p>Yet, if not addressed, Hamas may continue to operate irrespective of what happens on the surface. Indeed, as many of the tunnels lead across the border, there is a risk of further incursions, rocket strikes and attacks on IDF forces. And, given the heavily urbanised nature of Gaza, much of the network is <a href="https://www.theguardian.com/world/2023/oct/30/human-shield-israel-claim-hamas-command-centre-under-hospital-palestinian-civilian-gaza-city">beneath civilian infrastructure</a>, which further complicates Israeli operations.</p>
<p>Hamas is a proficient and prolific user of tunnels. But in honing its expertise, the group has also provided Israeli forces with a decades-long crash course in how to deal with their underground operations. </p>
<p>In addition to their own experience with Hamas tunnels, the IDF can also draw upon lessons from the war on terror, where coalition forces had to contend with both <a href="https://www.washingtonpost.com/news/worldviews/wp/2017/04/14/the-islamic-state-has-tunnels-everywhere-its-making-them-much-harder-to-defeat/">natural and purpose-built tunnels</a>, and even US experiences with <a href="https://apps.dtic.mil/sti/pdfs/AD1083168.pdf#page=%5B34%5D">drug cartels burrowing</a> on their southern border with Mexico.</p>
<h2>Bitter experience</h2>
<p>While Hamas is counting on its tunnels to cause problems, Israel already has a range of solutions. It has already gained valuable experience in underground operations, having learned hard lessons from the past. A range of innovative <a href="https://en.globes.co.il/en/article-us-congressional-committee-approves-israel-tunnel-detection-aid-1001031996">purpose-built technologies</a> and strategies can be used to provide the IDF with a technological edge. </p>
<p>Some are simple, such as <a href="https://www.nytimes.com/2013/02/21/world/middleeast/egypts-floods-smuggling-tunnels-to-gaza-with-sewage.html">flooding tunnels with sewage</a>, whereas others are more complex, involving specialised engineering. Some solutions, such as <a href="https://www.ausairpower.net/GBU-28.html">ground-penetrating explosives</a>, might be difficult to use, given the presence of civilians.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1714715794515304516"}"></div></p>
<p>Israel has known about the tunnels for a long time and is taking them seriously. <a href="https://news.sky.com/story/israel-says-it-has-attacked-gunmen-inside-hamas-tunnels-and-releases-video-from-gaza-12997068">Recent operations</a> suggest that the time spent training for <a href="https://en.globes.co.il/en/article-simulators-training-idf-soldiers-for-tunnel-warfare-1001026216">this exact scenario</a> is going to pay off, at least to a certain extent. </p>
<p>But dealing with a network of more than <a href="https://www.cbsnews.com/news/israel-hamas-war-news-targets-tunnel-network-gaza-next-phase/">300 miles</a> is still going to represent a massive challenge, and storming or blocking off every part of the system is probably impossible.</p>
<p>Bitter experience has taught Israel most of Hamas’s tactics already – but this does not mean that the group doesn’t have more tricks up its sleeve. Hamas’s recent offensive success was rooted in the way it used a number of relatively low-level capabilities in concert.</p>
<p>For instance, paragliders, ground assaults and rockets only have a limited impact when used individually, but together, were used to devastating effect <a href="https://www.foreignaffairs.com/israel/catastrophic-success-hamas">on October 7</a>.</p>
<p>Now Hamas will be hoping for the same degree of success when acting on the defensive. Depending on how Israel chooses to deal with the issue, they may find their ground forces bogged down in slow-moving subterranean activity, or risk heavy civilian casualties if they simply choose to bomb or collapse the tunnels. </p>
<p>Almost any solution Israel chooses can be turned into a Hamas advantage: both in military and political terms.</p>
<p>Ultimately Israel has no perfect solution to the complex problem posed by the Hamas underground network. But years of dealing with the Hamas Metro means the IDF is not entirely unequipped to confront the challenge. </p>
<p>It seems inevitable that the next days and weeks will be a bitter and bloody struggle, both in the streets of Gaza and as deep as 70 metres below ground.</p><img src="https://counter.theconversation.com/content/216767/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Christopher Morris does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>
Hamas’s 300 mile network of tunnels under Gaza is going to prove difficult and perhaps deadly for Israeli troops attempting a ground war in the territory.
Christopher Morris, Teaching Fellow, School of Strategy, Marketing and Innovation, University of Portsmouth
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/181454
2022-04-26T12:35:06Z
2022-04-26T12:35:06Z
Going underground: Ukraine’s subterranean fighters highlight the benefit – and long history – of tunnels in warfare
<figure><img src="https://images.theconversation.com/files/459531/original/file-20220425-26-z10wv.jpg?ixlib=rb-1.1.0&rect=0%2C51%2C3431%2C2229&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Ukrainian fighters entering a tunnel.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/ukrainian-soldiers-walk-through-a-tunnel-of-a-trench-on-the-news-photo/1239919477?adppopup=true">Anatolii Stepanov/AFP via Getty Images</a></span></figcaption></figure><p>Faced with the prospect of sending Russian troops into subterranean combat, Vladimir Putin demurred. “There is no need to climb into these catacombs and crawl underground,” he <a href="https://www.reuters.com/world/europe/putin-cancels-russian-plans-storm-mariupol-steel-plant-opts-blockade-instead-2022-04-21/">told his defense minister on April 21, 2022</a>, ordering him to cancel a planned storming of a steel plant in the besieged Ukrainian port city of Mariupol.</p>
<p>While Putin’s back-up plan – to form a seal around trapped Ukrainian forces and wait it out – is no less brutal and there are reports that Russians <a href="https://www.reuters.com/world/europe/ukrainian-presidential-adviser-says-russian-forces-trying-storm-azovstal-plant-2022-04-24/">may still have mounted an offensive on the site</a>, Putin’s hesitancy to send his forces into a sprawling network of tunnels under the complex hints at a truth in warfare: Tunnels can be an effective tool in resisting an oppressor.</p>
<p>Indeed since the war began in February, reports have emerged of Ukrainian defenders <a href="https://www.dailymail.co.uk/news/article-10714221/Ukrainian-tunnel-fighters-Mariupol-hellish-stand-Stalingrad-esque-steel-plant.html">using underground tunnel networks</a> in efforts to deny Russian invaders control of major cities, as well as <a href="https://www.newyorker.com/news/dispatch/preparing-odesas-catacombs-for-a-russian-assault">to provide sanctuary</a> <a href="https://www.rferl.org/a/ukraine-invasion-kyiv-underground-shelter-russia/31721685.html">for civilians</a>.</p>
<p>As an <a href="https://www.airuniversity.af.edu/ACSC/Display/Article/2480528/department-of-research/">expert in military history and theory</a>, I know there is sound thinking behind <a href="https://www.files.ethz.ch/isn/190444/springer_-_tunneling_in_warfare.pdf">using tunnels as both a defensive and offensive tactic</a>. Such networks allow small units to move undetected by aerial sensors and emerge in unexpected locations to launch surprise attacks and then essentially disappear. For an invader who does not possess a thorough map of the subterranean passages, this can present a nightmare scenario, leading to massive personnel losses, plummeting morale and an inability to finish the conquest of their urban objective – all factors that may have factored in Putin’s <a href="https://www.cbsnews.com/news/mariupol-ukraine-putin-russia-plans-cancel/">decision not to send troops underground</a> in Mariupol.</p>
<h2>A history of military tunneling from ancient roots</h2>
<p>The use of tunnels and underground chambers in times of conflict is nothing new.</p>
<p>The use of tunnels has been a <a href="https://www.fpri.org/article/2015/04/fighting-under-the-earth-the-history-of-tunneling-in-warfare/">common aspect of warfare for millennia</a>. Ancient besieging forces used tunneling operations as a means to weaken otherwise well-fortified positions. This typically required engineers to construct long passages under walls or other obstacles. Collapsing the tunnel weakened the fortification. If well-timed, an assault conducted in the immediate aftermath of the breach might lead to a successful storming of the defended position. </p>
<p>One of the earliest examples of this technique is <a href="https://blog.britishmuseum.org/introducing-the-assyrians/">depicted on Assyrian carvings</a> that are thousands of years old. While some attackers climb ladders to storm the walls of an Egyptian city, others can be seen digging at the foundations of the walls. </p>
<figure class="align-center ">
<img alt="An engraving shoes Assyrian fighters climbing ladders, engaged in combat and digging tunnels under a fortification." src="https://images.theconversation.com/files/459477/original/file-20220425-12-1manao.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/459477/original/file-20220425-12-1manao.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=436&fit=crop&dpr=1 600w, https://images.theconversation.com/files/459477/original/file-20220425-12-1manao.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=436&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/459477/original/file-20220425-12-1manao.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=436&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/459477/original/file-20220425-12-1manao.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=548&fit=crop&dpr=1 754w, https://images.theconversation.com/files/459477/original/file-20220425-12-1manao.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=548&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/459477/original/file-20220425-12-1manao.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=548&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Assyrian engraving of the siege of an Egyptian fort.</span>
<span class="attribution"><a class="source" href="https://blog.britishmuseum.org/introducing-the-assyrians/">The Trustees of the British Museum</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p><a href="https://www.warhistoryonline.com/ancient-history/roman-sieges-used-mining-operations.html">Roman armies</a> relied heavily upon sophisticated engineering techniques such as putting arches into the tunnels they built during sieges. Roman defenders also perfected the <a href="https://www.wbur.org/hereandnow/2014/07/21/history-tunnel-warfare">art of digging counter-tunnels</a> to intercept those used by attackers before they presented a threat. Upon penetrating an enemy tunnel, they flooded it with caustic smoke to drive out the enemy or launched a surprise attack upon unsuspecting miners.</p>
<p>The success of tunneling under fortifications led European engineers in the Middle Ages to design ways to thwart the tactic. They built castles on bedrock foundations, making any attempt to dig beneath them much slower, and <a href="https://www.exploring-castles.com/castle_designs/medieval_castle_defence/">surrounded walls with moats</a> so that tunnels would need to be far deeper. </p>
<p>Although tunneling remained an important aspect of sieges through the 13th century, it was eventually replaced by the introduction of gunpowder artillery – which proved a more effective way to breach fortifications. </p>
<p>However, by the mid-19th century, advances in mining and tunnel construction led to a resurgence in subterranean approaches to warfare.</p>
<p>During the Crimean War in the 1850s, British and French attackers attempted to tunnel under Russian fortifications at the <a href="https://historyofyesterday.com/hell-on-earth-the-siege-of-sevastopol-d9c5b1a5f757">Battle of Sevastopol</a>. Ten years later, Ulysses S. Grant authorized an attempt to tunnel <a href="https://www.battlefields.org/learn/articles/calamity-crater">under Confederate defenses</a> at the siege of Petersburg, Virginia. In both cases, large caches of gunpowder were placed in chambers created by tunneling under key positions and detonated in coordination with an infantry assault. </p>
<h2>Tunneling in the age of airpower</h2>
<p>With warfare increasingly relying on aircraft in the 20th century, military strategists again turned to tunnels – undetectable from the skies and protected from falling bombs.</p>
<figure class="align-center ">
<img alt="Black and white photo shows two soldiers in the First World War listening to a device while sat in a tunnel." src="https://images.theconversation.com/files/459556/original/file-20220425-13-obg0jq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/459556/original/file-20220425-13-obg0jq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=449&fit=crop&dpr=1 600w, https://images.theconversation.com/files/459556/original/file-20220425-13-obg0jq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=449&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/459556/original/file-20220425-13-obg0jq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=449&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/459556/original/file-20220425-13-obg0jq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=565&fit=crop&dpr=1 754w, https://images.theconversation.com/files/459556/original/file-20220425-13-obg0jq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=565&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/459556/original/file-20220425-13-obg0jq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=565&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Listening in under enemy lines during the First World War.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/world-war-i-listening-in-a-tunnel-under-the-enemy-lines-in-news-photo/526496610?adppopup=true">adoc-photos/Corbis via Getty Images)</a></span>
</figcaption>
</figure>
<p>In World War I, tunneling was attempted as a means to launch surprise attacks on the Western Front, potentially bypassing the other side’s system of trenches and remaining undetected by aerial observers. In particular, the <a href="https://www.sciencedirect.com/science/article/abs/pii/S1296207416304216">Ypres salient</a> in war-ravaged Belgium was the site of hundreds of tunnels dug by British and German miners, and the horrifying stories of combat under the earth provide one of the most terrifying vignettes of that awful war.</p>
<p>During World War II, Japanese troops in occupied areas in the Pacific <a href="https://www.atlasobscura.com/places/japanese-tunnels-of-baguio">constructed extensive tunnel networks</a> to make their forces virtually immune to aerial attack and naval bombardment from Allied forces. During amphibious assaults in places such as the Philippines and <a href="https://www.businessinsider.com/iwo-jima-world-war-ii-battle-photo-marines-japan-backstory-2018-2">Iwo Jima</a>, American and Allied forces had to contend with a warren of Japanese tunnel networks. Eventually they resorted to using high explosives to collapse tunnel entrances, <a href="https://www.nytimes.com/1995/03/15/world/iwo-jima-journal-a-pacific-isle-that-can-t-quite-rest-in-peace.html">trapping thousands</a> of Japanese troops inside. </p>
<p>The <a href="https://www.history.com/topics/vietnam-war/cu-chi-tunnels">Viet Cong tunnel networks</a>, particularly in the vicinity of Saigon, were an essential part of their guerrilla strategy and remain a popular tourist stop today. Some of the tunnels were large enough to house hospital and barracks facilities and strong enough to withstand anything short of nuclear bombardment.</p>
<figure class="align-center ">
<img alt="A drawing depicts men and women crawling along a tunnel structure in Vietnam" src="https://images.theconversation.com/files/459553/original/file-20220425-2721-wwyj5d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/459553/original/file-20220425-2721-wwyj5d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=392&fit=crop&dpr=1 600w, https://images.theconversation.com/files/459553/original/file-20220425-2721-wwyj5d.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=392&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/459553/original/file-20220425-2721-wwyj5d.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=392&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/459553/original/file-20220425-2721-wwyj5d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=493&fit=crop&dpr=1 754w, https://images.theconversation.com/files/459553/original/file-20220425-2721-wwyj5d.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=493&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/459553/original/file-20220425-2721-wwyj5d.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=493&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Diagram of typical tunnel structure in Cu-Chi, Vietnam.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/cu-chi-tunnels-vietman-asie-news-photo/947633266?adppopup=true">Didier Noirot/Gamma-Rapho via Getty Images</a></span>
</figcaption>
</figure>
<p>The tunnels not only protected Vietnamese fighters from overwhelming American airpower, they also facilitated hit-and-run style attacks. Specialized “<a href="https://www.nytimes.com/2018/02/09/opinion/vietnam-war-tunnel-rat.html">tunnel rats</a>,” American soldiers who ventured into the tunnels armed only with a knife and pistol, became adept at navigating the tunnel networks. But they could not be trained in sufficient numbers to negate the value of the tunnel systems.</p>
<h2>Tunnels for terrorism</h2>
<p>In the 21st century, tunnels have been used to facilitate the activities of terror organizations. During the American-led invasion of Afghanistan, military operatives soon discovered that al-Qaida had fortified a series of tunnel networks connecting naturally occurring caves in the <a href="https://www.govinfo.gov/content/pkg/CPRT-111SPRT53709/html/CPRT-111SPRT53709.htm">Tora Bora</a> region.</p>
<p>Not only did they hide the movement of troops and supplies, they <a href="https://www.govinfo.gov/content/pkg/CPRT-111SPRT53709/html/CPRT-111SPRT53709.htm">proved impervious to virtually every weapon</a> in the U.S.-led coalition’s arsenal. The complexes included air filtration systems to prevent chemical contamination, as well as massive storerooms and sophisticated communications gear allowing al-Qaida leadership to maintain control over their followers.</p>
<p>And tunneling activity <a href="https://www.npr.org/2021/06/04/1003387937/civilians-paid-a-steep-price-for-destroyed-tunnels-in-israeli-hamas-conflict">in and around Gaza</a> continues to provide a tool for Hamas to <a href="https://www.washingtonpost.com/news/morning-mix/wp/2014/07/21/how-hamas-uses-its-tunnels-to-kill-and-capture-israeli-soldiers/">get fighters into Israeli territory</a>, while at the same time allowing Palestinians to circumvent Israel’s blockade of Gaza’s borders.</p>
<h2>Soviet tunnels and Ukraine</h2>
<p>Many of the tunnels being utilized today in Ukrainian efforts to defend the country were built in the Cold War-era, when the United States <a href="https://www.airforcemag.com/article/0601overfly/">routinely engaged in overflights</a> of Soviet territory.</p>
<p>To counteract the significant air and satellite advantage <a href="https://www.statista.com/statistics/1293174/nato-russia-military-comparison/">held by the United States and NATO</a>, the Soviet military dug underground passages under major population centers. </p>
<p>These subterranean systems offered a certain amount of shelter for the civilian population in the event of a nuclear attack and allowed for the movement of military forces unobserved by the ever-present eyes in the sky. </p>
<p>[<em>Over 150,000 readers rely on The Conversation’s newsletters to understand the world.</em> <a href="https://memberservices.theconversation.com/newsletters/?source=inline-150ksignup">Sign up today</a>.]</p>
<p>These same tunnels serve to connect much of the <a href="https://www.france24.com/en/live-news/20220413-mariupol-s-tunnel-warriors-seek-to-slow-russian-onslaught">industrial infrastructure</a> in Mariupol today – and have become a <a href="https://www.cbsnews.com/news/mariupol-ukraine-putin-russia-plans-cancel/">major asset</a> for the outnumbered Ukrainian forces.</p>
<p>Other Ukrainian cities have similar systems, some dating back centuries. For example, Odesa, another key Black Sea port, has a <a href="https://www.thedrive.com/the-war-zone/44745/odesas-massive-maze-like-catacombs-could-be-bad-news-for-russian-invaders">catacomb network</a> stretching over 2,500 kilometers. It began as part of a limestone mining effort – and to date, there is <a href="https://www.thedrive.com/the-war-zone/44745/odesas-massive-maze-like-catacombs-could-be-bad-news-for-russian-invaders">no documented map</a> of the full extent of the tunnels. </p>
<p>In the event of a Russian assault on Odesa, the local knowledge of the underground passages might prove to be an extremely valuable asset for the defenders. The fact that more than 1,000 entrances to the catacombs have been identified should surely give Russian attackers pause before commencing any attack upon the city – just as the tunnels under a steelworks in Mariupol forced Putin to rethinks plans to storm the facility.</p><img src="https://counter.theconversation.com/content/181454/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Paul J. Springer is a Senior Fellow of the Foreign Policy Research Institute. His comments represent his own opinion and do not reflect the official policy of the United States Government, the U.S. Department of Defense, or the U.S. Air Force.</span></em></p>
Ukrainian fighters are utilizing a maze of tunnels in Mariupol and other key cities. The use of the underground in conflict has a rich history.
Paul J. Springer, Professor of Comparative Military Studies, Air University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/144276
2020-09-13T19:51:23Z
2020-09-13T19:51:23Z
What lies beneath: tunnels for trafficking, or just a subterranean service? Time to rescue these spaces from the conspiracists
<figure><img src="https://images.theconversation.com/files/352199/original/file-20200811-16-1bt1gkt.jpg?ixlib=rb-1.1.0&rect=177%2C0%2C2646%2C1812&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A tidal drain at South Yarra, Melbourne, in 2008. The installation of litter-trapping equipment now prevents access.</span> <span class="attribution"><span class="source">Photo: Victoria Kolankiewicz</span>, <span class="license">Author provided</span></span></figcaption></figure><p>Digital communications have <a href="https://theconversation.com/are-conspiracy-theories-on-the-rise-in-the-us-121968">spread conspiracy theories more widely than ever before</a>, particularly in this uncertain and tumultuous year. QAnon, for example, is <a href="https://theconversation.com/how-conspiracy-theories-spread-online-its-not-just-down-to-algorithms-133891">a movement</a> that seeks to identify a “deep state” or “global elite” complicit in <a href="https://theconversation.com/the-church-of-qanon-will-conspiracy-theories-form-the-basis-of-a-new-religious-movement-137859">human trafficking, “Pizzagate” and the orchestration of a global pandemic</a>. One conspiracy theory “<a href="https://www.reuters.com/article/uk-factcheck-children-rescued-tunnels/fact-check-35000-malnourished-and-caged-children-were-not-recently-rescued-from-tunnels-by-us-military-idUSKBN23M2EL">going viral</a>” is that extensive operations are taking place to rescue children held in secret underground locales beneath densely populated cities. </p>
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Read more:
<a href="https://theconversation.com/how-conspiracy-theories-spread-online-its-not-just-down-to-algorithms-133891">How conspiracy theories spread online – it's not just down to algorithms</a>
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<p>Tunnel networks beneath major Australian cities such as <a href="https://twitter.com/BushmansMum/status/1287181188860227586">Melbourne</a> and <a href="https://twitter.com/timetowakeupsw1/status/1246785772268683265">Sydney</a> have <a href="https://www.facebook.com/sarah.shanahan.58/posts/10157286425985685">received similar treatment</a>. Misconceptions of their form and purpose are communicated via social media. The stuff of urban legends, once circulated among acquaintances, is now online. </p>
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<p>The misunderstandings of these spaces reveal a more glaring oversight: of wartime histories, transportation follies, essential services and the unique geologies and climates that require drainage infrastructure. These tunnels are hidden by necessity. But they are close enough to the surface to be easily accessible, preventing their use for any large-scale conspiracy.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/356898/original/file-20200908-20-1652fnm.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A Facebook post of conspiracy theory linking Melbourne lockdown to children held captive in underground tunnels" src="https://images.theconversation.com/files/356898/original/file-20200908-20-1652fnm.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/356898/original/file-20200908-20-1652fnm.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=596&fit=crop&dpr=1 600w, https://images.theconversation.com/files/356898/original/file-20200908-20-1652fnm.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=596&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/356898/original/file-20200908-20-1652fnm.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=596&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/356898/original/file-20200908-20-1652fnm.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=749&fit=crop&dpr=1 754w, https://images.theconversation.com/files/356898/original/file-20200908-20-1652fnm.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=749&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/356898/original/file-20200908-20-1652fnm.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=749&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A Facebook post linking the Melbourne COVID-19 lockdown to children held captive in underground tunnels.</span>
<span class="attribution"><a class="source" href="https://www.facebook.com/sarah.shanahan.58/posts/10157286425985685">Facebook</a></span>
</figcaption>
</figure>
<h2>Why the fixation with tunnels?</h2>
<p>Abandoned or atypical urban spaces have <a href="https://theconversation.com/reopening-londons-mail-rail-why-its-so-hard-to-recreate-the-thrill-of-exploring-urban-ruins-54423">long piqued the public imagination</a>. Sites of abandonment are also associated with notions of freedom and excitement. Urban exploration has increased significantly within the past decade, amplified by social media sharing of imagery and aesthetics. </p>
<p>Rumours abound of complex tunnel networks in major Australian cities, created in the wake of the second world war. Larger air raid shelters were often located close to urban settlement, but escaped use. They remained in public memory as mythology: bunkers can be located across Australia, from Dover Heights in Sydney, to Prospect and Glenelg in Adelaide. <a href="https://www.brisbanetimes.com.au/national/queensland/the-only-air-raid-pipe-shelters-in-brisbane-still-remain-a-mystery-20190425-p51h4u.html">Over 20 air raid shelters exist in Brisbane alone</a>. </p>
<figure class="align-center ">
<img alt="Entrances to air raid shelter at Howard Smith Wharves, Brisbane" src="https://images.theconversation.com/files/352166/original/file-20200811-22-4u2nru.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/352166/original/file-20200811-22-4u2nru.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/352166/original/file-20200811-22-4u2nru.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/352166/original/file-20200811-22-4u2nru.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/352166/original/file-20200811-22-4u2nru.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/352166/original/file-20200811-22-4u2nru.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/352166/original/file-20200811-22-4u2nru.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The entrances to an air raid shelter at Howard Smith Wharves, Brisbane.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Air_raid_shelters_at_Howard_Smith_Wharves_in_Brisbane_02.jpg">Kgbo/Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>The fabled “<a href="https://www.heraldsun.com.au/leader/north/a-tunnel-in-the-banks-of-the-merri-creek-has-finally-been-filled-in-by-darebin-council/news-story/5c811dc980967ebc61e9321ec222a0b4">Northcote Tunnel</a>” in Melbourne was the subject of decades of rumour. It was eventually found to be the result of a search for an underground stream, not the large-scale 1940s American construction it was said to be. </p>
<p>Tunnels beneath Sydney served similar purposes, either by design or as the result of a failed transport infrastructure project. The St James tunnels are a prime example. This “hidden” space is about to be converted to <a href="https://www.smh.com.au/national/nsw/st-james-tunnel-vision-plan-to-revive-abandoned-sydney-railway-20181001-p5073u.html">a tourism precinct</a>. </p>
<p>Beneath the streets of Melbourne, Sydney and beyond, mail and precious cargo were often transported about the city in underground tunnels from nearby railway stations or ports to parliament or the <a href="https://en.wikipedia.org/wiki/General_Post_Office,_Melbourne">General Post Office</a>. </p>
<h2>So what are these spaces used for today?</h2>
<p>Today, urban tunnels carry telecommunications, gas, electricity, water and sewerage infrastructure.</p>
<p>Exact locations remain secret for security and operational reasons. Access is allowed in rare cases. In the case of the <a href="http://www.health.vic.gov.au/healthvictoria/sep11/tunnel.htm">Royal Melbourne Hospital steam tunnels</a>, members of the public can book a place on once-yearly tours. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/352165/original/file-20200811-24-1b63gmi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Partially constructed tunnels and unused platforms at St James railway station, Sydney." src="https://images.theconversation.com/files/352165/original/file-20200811-24-1b63gmi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/352165/original/file-20200811-24-1b63gmi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/352165/original/file-20200811-24-1b63gmi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/352165/original/file-20200811-24-1b63gmi.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/352165/original/file-20200811-24-1b63gmi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/352165/original/file-20200811-24-1b63gmi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/352165/original/file-20200811-24-1b63gmi.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Partially constructed tunnels and unused platforms at St James railway station, Sydney.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:St_James_Railway_Station_Sydney_IMG_4450_(26443308184).jpg">Beau Giles/Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Stormwater drains are most abundant in urban areas; perhaps this is why they feature so heavily in conspiracies. Where depressions, undulations or linear tracts of open space exist in the landscape, a stormwater drain is likely lurking beneath the surface. These drains are needed to divert rainwater from areas where hard surfaces would otherwise lead to flooding. </p>
<p>In Melbourne, the <a href="https://www.melbournewater.com.au/water-data-and-education/water-facts-and-history/history-and-heritage/timeline-our-history">Melbourne and Metropolitan Board of Works</a> started building these drains in the early 20th century. I have explored many of these complex networks, <a href="https://www.melbournewater.com.au/water-data-and-education/water-facts-and-history/flooding/drainage-system">over 1,400 kilometres of drains</a> that span almost all of metropolitan Melbourne and its fringes. These drains are literally beneath the feet of city dwellers: many would be surprised to find that a drain runs <a href="https://www.theage.com.au/national/victoria/a-plan-to-turn-melbournes-elizabeth-street-into-a-rainforest-canal-20150304-13uk1x.html">beneath the major thoroughfare of Elizabeth Street</a>, historically Williams Creek. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1287181188860227586"}"></div></p>
<p>The Metropolitan Water Sewerage and Drainage Board built similar infrastructure in Sydney. Open and closed conduits were built in concrete and brick — as well as bluestone in Melbourne, and limestone in Sydney — throughout the past century. Sydney’s stormwater network <a href="https://www.sydneywater.com.au/sw/water-the-environment/how-we-manage-sydney-s-water/stormwater-network/index.htm">totals 454 kilometres</a> of drains and spans 73 water catchments. These drains ultimately carry <a href="https://www.smh.com.au/environment/where-does-all-the-stormwater-go-after-the-sydney-weather-clears-20150430-1mx4ep.html">500 billion litres into Sydney Harbour or Botany Bay</a>. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/our-legacy-of-liveable-cities-wont-last-without-a-visionary-response-to-growth-93729">Our legacy of liveable cities won't last without a visionary response to growth</a>
</strong>
</em>
</p>
<hr>
<figure class="align-center ">
<img alt="A drain on the Yarra River in South Yarra" src="https://images.theconversation.com/files/352197/original/file-20200811-18-1506vqx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/352197/original/file-20200811-18-1506vqx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=384&fit=crop&dpr=1 600w, https://images.theconversation.com/files/352197/original/file-20200811-18-1506vqx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=384&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/352197/original/file-20200811-18-1506vqx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=384&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/352197/original/file-20200811-18-1506vqx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=483&fit=crop&dpr=1 754w, https://images.theconversation.com/files/352197/original/file-20200811-18-1506vqx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=483&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/352197/original/file-20200811-18-1506vqx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=483&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A tidal drain at South Yarra, Melbourne, in 2008. The installation of litter-trapping equipment now prevents access.</span>
<span class="attribution"><span class="source">Photo: Victoria Kolankiewicz</span></span>
</figcaption>
</figure>
<h2>Dangerous, yes, but for more mundane reasons</h2>
<p>These hidden spaces <em>can</em> be controversial or dangerous, but not for the reasons put forth by QAnon and its ilk. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-church-of-qanon-will-conspiracy-theories-form-the-basis-of-a-new-religious-movement-137859">The Church of QAnon: Will conspiracy theories form the basis of a new religious movement?</a>
</strong>
</em>
</p>
<hr>
<p>Social groups have emerged around drain exploration, with the Melbourne-based Cave Clan the best-known example. They have clear rules to ensure the safety of their members. “No drains when it rains” is one such rule: sudden rain can catch out explorers as water levels rise quickly inside drains. </p>
<p>Drownings have been reported in both <a href="https://www.news.com.au/national/graffiti-drain-survivor-i-wish-i-had-died/news-story/40a663ce61814480552ad5348ea0d698?sv=d13fa3e80fab16b57ee6743c223cf149">Sydney</a> and <a href="https://www.heraldsun.com.au/news/victoria/fears-for-lives-of-underground-explorers/news-story/e9a23d2f83212308d5a3b8928700fa07">Melbourne</a>. The unpredictability of sudden torrential flows means these spaces are fundamentally unsuited to the purposes suggested in conspiracy theories.</p>
<p>Frequent visits by urban explorers would also quickly identify any secretive mis-uses of drainage infrastructure. This would equally apply to other underground spaces such as steam and service tunnels – maintenance staff would soon spot anything amiss.</p>
<p>More crucial, however, is that the design of these drains means they could not play any part in supposed trafficking networks. Some of these drains are large enough for adults to explore. The vast majority, though, are too small to be accessed, with diameters as narrow as 300mm. </p>
<p>Even the most cavernous drains would not be suitable for storage. Larger drains are designed to hold larger flows, often at a confluence of catchment areas. While they these drains <em>could</em> host human beings, they would be at risk of drowning whenever it rained. Tidal flows or litter traps can also prevent access.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/if-the-tide-is-high-our-sewerage-systems-wont-hold-on-14467">If the tide is high, our sewerage systems won't hold on</a>
</strong>
</em>
</p>
<hr>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1284427769393233920"}"></div></p>
<p>Child trafficking is a very <a href="https://theconversation.com/human-trafficking-and-slavery-still-happen-in-australia-this-comic-explains-how-112294">relevant</a> <a href="https://theconversation.com/jeffrey-epsteins-arrest-is-the-tip-of-the-iceberg-human-trafficking-is-the-worlds-fastest-growing-crime-120225">issue</a>, but it is certainly not taking place under cities across the nation. Rather than abandoning subterranean spaces to conspiratorial narratives or urban mythology, these spaces are important for other reasons. These point to the need to build a common understanding not only of their form and function, but also of the ethos underlying their existence, a concern for the common good. </p>
<p>That something as impressive and as everyday as our civic infrastructure inspires such fascination and fear is indeed curious. Ultimately, these spaces are too utilitarian to serve the purpose claimed by viral social media posts.</p><img src="https://counter.theconversation.com/content/144276/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Victoria Kolankiewicz does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>
What was once the stuff of urban legends now spreads virally through social media claims the tunnels beneath our cities are used for child trafficking. The truth is both more mundane and important.
Victoria Kolankiewicz, Research Assistant, Australian Centre for Architectural History, Urban and Cultural Heritage, The University of Melbourne
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/82042
2017-08-09T11:27:32Z
2017-08-09T11:27:32Z
The German Great Escape: the science of how 83 military officers tunnelled out of a Welsh prison camp in 1945
<figure><img src="https://images.theconversation.com/files/181526/original/file-20170809-26064-1vt9372.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Plotting a route out? German prisoners in Britain during WWII.</span> <span class="attribution"><span class="source">Ministry of Information Photo Division Photographe</span></span></figcaption></figure><p>It only takes the opening notes of the theme tune to 1963 classic film <a href="http://www.imdb.com/title/tt0057115/">The Great Escape</a> for most people to conjure up images of the lives of prisoners of wars – and their escapes – during World War II. The film, based on the best-selling book of the same name, tells the story of how British Commonwealth prisoners escaped from Stalag Luft III in Sagan (now Żagań, Poland), in Nazi Germany.</p>
<p>This escape was not unique – there were an estimated 69 other mass escapes of prisoners of war during the war. In seven of these it was by German prisoners escaping. Now our new scientific investigation, <a href="http://dx.doi.org/10.1080/15740773.2017.1357900">published in the Journal of Conflict Archaeology</a>, reveals a hidden tunnel that allowed 83 German prisoners to escape from <a href="http://www.islandfarm.wales/">Camp 198</a> in Bridgend, South Wales, in March 1945.</p>
<p>Camp 198 had been established in 1944 in Bridgend to house 1,600 German officers. With the allies now squeezing the Germans on two fronts, the war had turned a corner, and prisoners were flooding in. In the UK alone, camps sprung up everywhere, numbered in a consecutive sequence that reached <a href="http://discovery.nationalarchives.gov.uk/details/r/C1367149">Camp 1026</a>, in order to house an estimated 400,000 prisoners. And with the <a href="http://hrlibrary.umn.edu/instree/y3gctpw.htm">Geneva Convention</a> specifying that officers could not be put to work in the fields, or anywhere else for that matter, there were undoubtedly many escape plans made.</p>
<p>Yet camp security measures at Bridgend were generally poor. Perhaps overwhelmed by the huge influx of enemy personnel, protocols for anti-escape measures took some time to develop. The lack of sentry towers and perimeter lighting on the fences meant that escape attempts were extremely likely. Tunnels had already proven to be the most common means of escape in the Great War – wherever ground conditions permitted it. The clay soils at Bridgend made it harder to dig tunnels than the sandy soils underlying the Stalag Luft III camp. However the Bridgend tunnels did not need as much shoring support to keep the tunnel intact, a bit of wood salvaged from huts did the trick.</p>
<p>We know the prisoners actually once started a tunnel that was discovered by the guards, perhaps breeding complacency among them. Whatever the case, it did not deter the would-be escapers, and it was a second tunnel, started in “Hut 9”, that finally allowed them to escape.</p>
<h2>Scientific investigation</h2>
<p>Left derelict when closed in 1948, Camp 198 was mostly demolished in the 1990s. However, Hut 9 was preserved by the local authorities, and remains in remarkable condition for scientists to investigate.</p>
<p>Hut 9 provides much evidence of the lives of the officer occupants, filling their days in captivity. Hand-drawn prisoner graffiti still adorns the prison walls. Much of it is poetry, referring to the “heimat” – home – or of loved ones. One of the graffitied walls in Hut 9 was false, constructed to hide the soil that was placed behind it and never discovered.</p>
<p>But what of the tunnel itself? Just as we did to locate <a href="http://dx.doi.org/10.1002/gea.20184">the missing tunnel “Dick”</a> near Hut 122 at the site of the Great Escape, Stalag Luft III, in 2003, we used geophysical investigations outside of Hut 9 at Bridgend to successfully detect the tunnel’s subsurface position. </p>
<p>We started the investigation by using <a href="http://onlinelibrary.wiley.com/doi/10.1002/9781118786352.wbieg0297/abstract">ground-based surface scanning</a> to create a surface model of the site. This helped us <a href="https://doi.org/10.1016/j.geomorph.2013.12.020">identify variations in the surface</a>, such as depressions which could indicate a collapsed tunnel. We then used ground penetrating radar surveys, which uses radar pulses to image the subsurface, to find the specific tunnel location (as well as plenty of tree roots).</p>
<p>At this point, we still weren’t ready to start digging. Measurements of electrical resistivity – how strongly a material opposes the flow of an electric current – helped us determine which parts of the tunnel were filled. Magnetic surveys, used to locate metallic objects, turned out to be less successful, as there was little metal within the tunnel.</p>
<p>While the escape tunnel at Stalag Luft III was dug some ten metres below ground – requiring some prodigious archaeological effort to reach it – at Bridgend, we discovered that the tunnel was at a relatively shallow level of 1.5 metres below ground level. Careful excavations by hand eventually helped us reach this tunnel, which was found to still be remarkably intact. Sawn-off wooden bed legs and materials from the prisoners’ huts, used to support the tunnel walls and roof, were still present, just as they had been left in 1945.</p>
<iframe src="https://drive.google.com/file/d/0B44anbUFlDinbmh3YzhxMmF0TlU/preview" width="100%" height="480"></iframe>
<p>Following the German escape, the local police, home guard, army and air force were all mobilised. While one group of prisoners stole a car and got as far as Birmingham, none managed to successfully make their way back to Germany. </p>
<p>By comparison, in the “Great Escape”, three people managed to return home. Of course, the Germans had to travel through the small, densely-populated island of the UK. The allied escapers achieved a much greater travel distance (470km versus 44km on average) than the Germans before being captured. They also had more sophisticated forged documents and escape material that would have significantly aided their escapes. </p>
<p>Given their comparatively simple plan, it is remarkable that so many Camp 198 prisoners managed to get out. And with the tunnel and the surrounding area destined to become a listed national monument and conserved for future generations, it may soon become as well remembered as the events described in the Great Escape.</p><img src="https://counter.theconversation.com/content/82042/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jamie Pringle receives funding from the HLF, the Nuffield Foundation, Royal Society, NERC, EPSRC and EU Horizon2020. He is affiliated with the Geological Society of London.</span></em></p><p class="fine-print"><em><span>Peter Doyle does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>
Scientists have uncovered a hidden tunnel left in remarkable condition at a now derelict prison in Bridgend, South Wales.
Jamie Pringle, Senior Lecturer in Engineering & Environmental Geosciences, Keele University
Peter Doyle, Head of Research Environment, London South Bank University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/81257
2017-07-19T04:25:59Z
2017-07-19T04:25:59Z
Tunnel exhaust stacks: don’t dare harm our kids … but expose workers
<figure><img src="https://images.theconversation.com/files/178765/original/file-20170719-13554-1ipv02.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The evidence that living near exhaust stacks from busy tunnels harms your lungs is far from settled.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/download/confirm/177485189?src=Z1gOTncP8SRuqj6YZnIphw-1-50&size=medium_jpg">from www.shutterstock.com</a></span></figcaption></figure><p>This week <a href="http://www.abc.net.au/news/2017-07-17/pollution-ventilation-shafts-for-western-harbour-tunnel-revealed/8711020">news broke</a> about the location of several exhaust ventilation stacks that will disperse vehicle pollution along some of the 14 kilometres of tunnels planned across Sydney.</p>
<p>Four of the six 20-35 metre tall exhaust stacks would be near schools, with the private girls’ school Wenona, Anzac Park Primary School in Cammeray and Seaforth Public School <a href="http://www.smh.com.au/nsw/schools-parks-homes-in-frame-as-sites-for-beaches-link-smokestacks-revealed-20170716-gxc9jg.html">each being within 200 metres</a>.</p>
<p>ABC TV’s 7pm Sydney news bulletin on Monday July 17 told viewers the stacks in the North Sydney area would be:</p>
<blockquote>
<p>near dozens of schools, pre-schools and parks … When the Lane Cove tunnel was built the unfiltered stacks were placed in the nearby industrial area. Residents want these stacks built in the Artarmon industrial estate and filtered.</p>
</blockquote>
<p>Eleven schools were <a href="http://www.abc.net.au/news/2017-07-17/pollution-ventilation-shafts-for-western-harbour-tunnel-revealed/8711020">named</a> in the online report.</p>
<h2>Does the evidence stack up?</h2>
<p>The Lane Cove tunnel stacks were the focus of a major research project conducted by some of Australia’s most renowned environmental health researchers in air quality and respiratory health.</p>
<p>They recruited 2,978 residents in the year before the tunnel opened (2006) and in each of two years afterwards (2007–2008).</p>
<p>These residents lived in one of four exposure zones, including a control zone. The residents completed a questionnaire about their respiratory symptoms in each of the three years. A sub-group of 380 people also had their lung function tested using <a href="http://lungfoundation.com.au/health-professionals/clinical-resources/copd/spirometry/">spirometry</a>, which measures how well someone can move air into and out of their lungs, and their ability to breathe out air (peak expiratory flow). This sub-group also recorded any symptoms twice a day for nine weeks.</p>
<p>Despite a major reduction in traffic from 90,000 to 45,000 vehicles a day along the main road the tunnel bypassed, <a href="http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0048921">there was no consistent evidence</a> that the respiratory health of people living along that road had improved.</p>
<p>However, people who lived near roads feeding into the tunnel reported more upper respiratory symptoms in the survey group but not in the panel sub-group. Those living within a radius of 650 metres of the tunnel ventilation stack also reported more upper and lower respiratory symptoms and had lower spirometric volumes (reflecting poorer lung health) after the tunnel opened. Although importantly, air pollutant levels near the stack did not increase over the study period.</p>
<h2>Unexpected results</h2>
<p>The authors said some of these results were “unexpected” because another <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2565655/">similar study</a> of an exhaust stack on Sydney’s M5 had shown no differences between before and after the exhaust started operation. </p>
<p>Their report discussed a number of methodological reasons to explain the Lane Cove findings (see the detailed discussion section <a href="http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0048921">here</a>).</p>
<p>The two Sydney studies undertaken on exhaust emissions through tunnel stacks have failed to produce unequivocal results about extra harms to those living nearby. While there is no debate about traffic pollution in urban areas contributing to <a href="https://woolcock.org.au/news-3/sydney-pollution-damaging-health-report">serious health consequences</a>, the argument that emissions from road tunnels and, particularly, their ventilation stacks pose serious risks to those living adjacent to them is far from convincing.</p>
<p>So decisions on where these stacks are placed will largely be driven, not by established risk metrics based on their distances from where people are breathing, but on outrage factors about exposed populations. </p>
<p>There is zero tolerance for even homeopathic levels of exposure when it comes to “industrial” particles like those from vehicles forced out of ventilation stacks. There is no community appetite to raise alarm about naturally sourced particles like pollen and dust that would be affecting the respiratory health of many of the children and adults living near or far from the proposed road and stacks.</p>
<p>But the idea that there might be added respiratory risk arising from traffic exhaust particles has animated some bizarre proposed solutions.</p>
<h2>Workers can cop any risk</h2>
<p>Twenty one years ago in 1996, in a parallel case again involving the Lane Cove region, I <a href="http://newsstore.fairfax.com.au/apps/viewDocument.ac?page=1&sy=nstore&kw=%22Simon+Chapman%22&pb=all_ffx&dt=selectRange&dr=entire&so=relevance&sf=author&rc=10&rm=200&sp=nrm&clsPage=1&docID=news960208_0021_4860">wrote about</a> the local council’s rules for where mobile phone towers could be sited. </p>
<p>As is still happening today, with the reported calls to locate the exhaust stacks in North Sydney “industrial” zones, sections of the community seem to assume it is acceptable to expose industrial-site workers, but not children, to exhaust stack emissions.</p>
<p>On the mobile phone tower siting regulations I wrote that if you live in the council district, the council will not allow a tower within 300 metres of your house. But if you work in the area, the towers can come as close as specified in any deal struck between your employer or a landowner and a phone company.</p>
<blockquote>
<p>They can plonk one right outside your office or factory window, in your car park, wherever … If you are in a school, any sort of child-care facility, a hospital or, most intriguingly, an aged care centre or “any recreational facility”, you won’t find a tower within 450 metres of you … Someone playing golf, bowls or having a picnic apparently cannot resist Radio Frequency Radiation like a worker can.</p>
</blockquote>
<p>I continued that along with infants, children, the sick and the elderly, those taking recreation get to enjoy an extra 150 metres buffer zone. Or at least while the kids are in day care or school. </p>
<blockquote>
<p>When they go home in the afternoon, the council thinks it’s OK to locate the towers up to 150 metres closer. Given that children spend more time at home than in school, the two different minimum distances cannot reflect any rational concern to minimum exposure.</p>
</blockquote>
<p>The mind-boggling irrationality of all this is apparently about to be reprised all over again with the siting of the new tunnel stacks.</p><img src="https://counter.theconversation.com/content/81257/count.gif" alt="The Conversation" width="1" height="1" />
As the latest controversy about tunnel exhaust stacks and respiratory health plays out in the media, some community members are proposing solutions that just don’t make sense.
Simon Chapman, Emeritus Professor in Public Health, University of Sydney
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/71451
2017-01-23T09:07:10Z
2017-01-23T09:07:10Z
Archaeologist: the A303 is a crucial part of Stonehenge’s setting
<figure><img src="https://images.theconversation.com/files/153660/original/image-20170120-5257-omr3r1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">© Pitt Rivers Museum (Accession Number 2012.79.21)</span></span></figcaption></figure><p><a href="http://www.english-heritage.org.uk/visit/places/stonehenge/">Stonehenge</a> has a traffic problem. The A303 has been the UK government’s preferred trunk road from London to the West Country since 1958 – but it runs within 165 metres of the 5,000-year-old monument. Narrowing to a single carriageway, it slows many a summertime car journey. The bottleneck brings noise and pollution, and presents a barrier to exploring the landscape on foot.</p>
<p>On January 12, Transport Secretary Chris Grayling announced plans for a <a href="https://www.theguardian.com/uk-news/2017/jan/12/stonehenge-a303-tunnel-chris-grayling-world-heritage-site">Stonehenge Bypass</a>, transforming the A303 into an “<a href="http://www.highways.gov.uk/roads/a303a358-work-to-create-an-expressway-to-the-south-west/">Expressway to the South West</a>”. It involves building a dual carriageway and tunnel across the <a href="http://whc.unesco.org/en/list/373">Stonehenge UNESCO World Heritage Site</a>. As Highways England launched a six-week <a href="https://highwaysengland.citizenspace.com/cip/a303-stonehenge/">public consultation</a> on the plan, the estimated cost of <a href="http://roads.highways.gov.uk/projects/a303-stonehenge-amesbury-and-berwick-down/">£1.4 billion</a> was <a href="https://historicengland.org.uk/whats-new/statements/stonehenge-a303/">heralded by Historic England</a> as “the biggest single investment ever made by government in this country’s heritage”. </p>
<p>But the Stonehenge Bypass is absolutely not in the best interests of cultural heritage.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/153658/original/image-20170120-5214-1p6sdft.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/153658/original/image-20170120-5214-1p6sdft.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/153658/original/image-20170120-5214-1p6sdft.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=330&fit=crop&dpr=1 600w, https://images.theconversation.com/files/153658/original/image-20170120-5214-1p6sdft.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=330&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/153658/original/image-20170120-5214-1p6sdft.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=330&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/153658/original/image-20170120-5214-1p6sdft.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=415&fit=crop&dpr=1 754w, https://images.theconversation.com/files/153658/original/image-20170120-5214-1p6sdft.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=415&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/153658/original/image-20170120-5214-1p6sdft.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=415&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Map of Stonehenge World Heritage Site with route of the proposed bypass and tunnel.</span>
<span class="attribution"><span class="source">Highways England</span></span>
</figcaption>
</figure>
<h2>Two old ideas</h2>
<p>The Stonehenge tunnel is, in fact, an old idea. Proposed in the 1989 <a href="https://en.wikipedia.org/wiki/Roads_for_Prosperity">Roads for Prosperity</a> government White Paper, which launched the last major programme of roadbuilding in England, over the subsequent three decades arguments over a variety of schemes have multiplied, at an estimated cost of <a href="https://books.google.co.uk/books?id=l9mjU90hoBUC&printsec=frontcover&dq=parker+pearson+stonehenge&hl=en&sa=X&ved=0ahUKEwiAuYvR8svRAhUFDcAKHRsCBZ0Q6AEIGjAA#v=onepage&q=%C2%A330%20million&f=false">£30m</a> in consultants’ and lawyers’ fees. </p>
<p>This time around, the project is billed as in the best interests of cultural heritage. The existing road “<a href="https://highwaysengland.citizenspace.com/cip/a303-stonehenge/supporting_documents/S160531%20A303%20Stonehenge%20case%20for%20scheme%20DEC_print.pdf">spoils the setting of Stonehenge</a>”, suggests Highways England. A new road would “improve our understanding and enjoyment of the Stonehenge monument,” chimes the joint National Trust and Historic England <a href="https://historicengland.org.uk/whats-new/statements/stonehenge-a303/">statement</a>.</p>
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<p>Another old idea is being revived hand-in-hand with the tunnel – heritage restoration. The focus is the stones, not their landscape. Stonehenge is reimagined as a Stone Age exhibit untouched by modernity. The A303 would be grassed over at the stones while a new road twice as wide is cut across the World Heritage Site, but tunnelled within the paying visitors’ view. The aesthetics of this “Stonehenge Restored” are determinedly Georgian. A stately monument within rolling lawns from which shuttles run along a new coaching-road between Bath and London. That carriageway hidden from the monument, so customers can stroll an “authentic” landscape of the past, never glimpsing the present.</p>
<h2>A living monument</h2>
<p>Why bury a road? The bypass plans turn back the clock to the kind of temporal connoisseurship widely dismissed since John Ruskin <a href="https://archive.org/stream/lampsofarchseven00ruskrich#page/194/mode/2up">argued in 1849 that</a>:</p>
<blockquote>
<p>Neither by the public, nor by those who have the care of public monuments, is the true meaning of restoration understood. It means the most total destruction … a destruction accompanied with false description of the thing destroyed.</p>
</blockquote>
<p>In Ruskin’s alternate vision of a “living monument”, the qualities of age-value and patina emerge through layers built up and eroded through human life and the passage of time. In the 1870s, this became the logic of William Morris’s “Anti-Scrape” movement – the world’s first heritage campaign. Ruskin and Morris understood that erasing later features to restore traces of some imagined original period leads not just to Georgian follies, but to downright misrepresentation.</p>
<p>The 21st-century “scraping” of Stonehenge would conjure the illusion of an unchanging Neolithic relic. But the monument has been a centre of gravity attracting human activity throug five millennia. The mosaic of henges, cursuses, round barrows, inhumations, settlements, enclosures, field systems – and even buildings and roads – represents an ongoing sequence of movement, building, living, and deposition. It’s the prime example of what WG Hoskins famously described as <a href="http://www.le.ac.uk/ebulletin-archive/ebulletin/features/2000-2009/2007/07/nparticle.2007-07-09.html">the “palimpsest” of the English landscape</a>, a layered document repeatedly written over. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/153253/original/image-20170118-26585-28yx4n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/153253/original/image-20170118-26585-28yx4n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/153253/original/image-20170118-26585-28yx4n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=340&fit=crop&dpr=1 600w, https://images.theconversation.com/files/153253/original/image-20170118-26585-28yx4n.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=340&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/153253/original/image-20170118-26585-28yx4n.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=340&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/153253/original/image-20170118-26585-28yx4n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=428&fit=crop&dpr=1 754w, https://images.theconversation.com/files/153253/original/image-20170118-26585-28yx4n.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=428&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/153253/original/image-20170118-26585-28yx4n.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=428&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Approach to Stonehenge in 1930, from the east: A303 running to the left, A344 (closed 2013) to the right.</span>
<span class="attribution"><span class="source">National Archives</span></span>
</figcaption>
</figure>
<p>This story encompasses the A303’s own history: laid out in the early 1800s as the “New Direct Road”, a coaching route from London to Exeter. It was less used from the 1840s with the railway boom, then became a major road from 1933, being defined as a trunk road by the Ministry of Transport in 1958. Stonehenge is not a site or an artefact, but an ever-changing landscape.</p>
<p>Driving west on the A303 today, we glimpse the monument. This modern view is endangered. Since the 1960s, archaeology’s <a href="http://rescue-archaeology.org.uk/">Rescue Movement</a> has defended our past against the threat of destruction from the present day. Today, it is Stonehenge’s modernity that is under threat from a narrow vision of the past.</p>
<p>Hiding the road from the stones would hide the stones from the public. Some <a href="http://www.alva.org.uk/details.cfm?p=423">1.3m people</a> will pass through the Stonehenge giftshop this year, but perhaps ten times that number will witness the monument from a passing vehicle. Those thrilling, often unexpected views may not be celebrated among the iconic experiences of global prehistory, but they are surely among the most democratic. Through these encounters, Stonehenge lives on as a public space. Year by year since the 1980s, public access to Stonehenge has been gradually restricted. This bypass would deal another blow to any chance of seeing the monument without paying the <a href="http://www.english-heritage.org.uk/visit/places/stonehenge/prices-and-opening-times">£15.50 entrance fee</a>. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/153341/original/image-20170118-26550-1d8a927.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/153341/original/image-20170118-26550-1d8a927.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=331&fit=crop&dpr=1 600w, https://images.theconversation.com/files/153341/original/image-20170118-26550-1d8a927.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=331&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/153341/original/image-20170118-26550-1d8a927.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=331&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/153341/original/image-20170118-26550-1d8a927.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=416&fit=crop&dpr=1 754w, https://images.theconversation.com/files/153341/original/image-20170118-26550-1d8a927.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=416&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/153341/original/image-20170118-26550-1d8a927.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=416&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">‘Stonehenge under threat’: the iconic image of the 1970s Rescue movement. © Rescue, The British Archaeological Trust.</span>
</figcaption>
</figure>
<h2>Save the A303!</h2>
<p>“Every age has the Stonehenge it deserves – or desires,” wrote visionary archaeologist <a href="https://jacquettahawkes.wordpress.com/">Jacquetta Hawkes</a> in 1967. What do we desire for Stonehenge today? </p>
<p>For some, the tunnel is <a href="https://mikepitts.wordpress.com/2015/10/29/tunnel-truths/">the best compromise</a>. New excavations would add to our understanding of the landscape (and bring jobs for archaeologists). Others call for <a href="http://www.bbc.co.uk/news/uk-england-wiltshire-38666455">a longer tunnel</a>. And some dismiss the project as a destructive “<a href="http://time.com/4632738/uk-government-stonehenge-tunnel/">time-bomb</a>”. After all, with sliproads and dual carriageways, the project could result in <a href="https://twitter.com/ProfDanHicks/status/821673131672829953">a net increase in road surface</a> within the World Heritage Site.</p>
<p>One promising idea is to <a href="http://www.spectator.co.uk/2017/01/the-stonehenge-tunnel-is-monumental-folly/">make the A303 one-way westbound</a>, building an alternative route for eastbound traffic away from the monument – cutting traffic at Stonehenge in half while saving millions. In preserving the A303, that solution reminds us of the ongoing lives of our ancient monuments in the modern world.</p>
<p>Stonehenge’s value lies not just in its prehistory, but also in its modernity. Today, the A303 is a crucial part of the monument’s setting. Yes, we must reduce the traffic. But why hide the stones from the world?</p><img src="https://counter.theconversation.com/content/71451/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Dan Hicks receives funding from the Economic and Social Research Council (ESRC) and the Arts and Humanities Research Council (AHRC). He is an Elected Trustee of the Society of Antiquaries of London.</span></em></p>
Stonehenge has a traffic problem. But building a £1.4 billion tunnel is not the answer.
Dan Hicks, Associate Professor and Curator, Pitt Rivers Museum and School of Archaeology, University of Oxford
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/16982
2013-10-03T14:02:22Z
2013-10-03T14:02:22Z
Explainer: how to build a tunnel
<figure><img src="https://images.theconversation.com/files/29353/original/m63qqt5w-1376580394.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Under the sea or through mountains, it's all the same.</span> <span class="attribution"><span class="source">Roger Wollstadt</span></span></figcaption></figure><p>Londoners will be aware that there is a lot of work going on under their feet at the moment. There is the new Crossrail railway with eight subterranean stations, expansion of Tottenham Court Road, Bond Street and Victoria London Underground stations, new cable tunnels and a huge new sewer tunnel. The digging is also set to continue well into the next decade, with many other projects underway.</p>
<p>And London is not alone. Cities need tunnels to function efficiently and sustainably, and to make them attractive places to live. Increasing urban populations in cities across the world are creating a huge demand for tunnels. As cities grow, the need to put trains, roads and utilities underground becomes unavoidable. Urban planners are beginning to recognise the benefits of using underground space and are coming up with novel ways of using it. In Norway there is an underground ice rink. In Hong Kong there are plans afoot to put sewage treatment facilities and waste transfer stations underground, freeing up the surface for development.</p>
<p>Tunnelling used to be one of those “black arts”, heavily based on experience and empirical data. Now, however, it is technologically advanced in both design and construction. Excavation is completely mechanised wherever possible, and miners are more likely to be seen behind a control panel than holding a shovel.</p>
<p>The daily running costs are high, and there isn’t space in the tunnel to throw more resources at the problem, so it is important to have the best people you can afford. It also makes tunnelling a 24/7 business, where working 12 hour shifts is the norm. </p>
<p>For long and reasonably straight tunnels of constant diameter, tunnel boring machines (TBMs) are used. They consist of a cylindrical steel can, called a shield, with a rotating cutterhead in front. The teeth or discs on the cutterhead break up the soil or rock, which passes through openings and onto a conveyor that carries the spoil out of the tunnel. </p>
<p>At the back of the TBM, precast concrete segments are brought in and erected to form a circular ring. The TBM pushes itself forward off the front face of the ring, excavating the ground again, until it has advanced far enough to insert another ring.</p>
<p>For shorter tunnels, tunnels that change size, turn sharp corners or have junctions, it is not possible to use a TBM. In the old days temporary timber support would have been used, followed by either a masonry or brick lining. This was quite slow, so in the late 19th century masonry and brick were largely superseded by cast iron rings. These rings came in segments that were bolted together, and these can be seen on many London Underground stations, including those on the Jubilee Line Extension (East of Green Park), built in the mid-1990s. Now sprayed concrete, also known as shotcrete, is more common.</p>
<p>Sprayed concrete is propelled using high pressure compressed air and the velocity of impact ensures the air is driven out of the concrete so it is dense, strong and durable. To help it stick, a chemical accelerator is added so that the concrete sets as soon as it hits the wall and quickly gains strength.</p>
<p>Tunnelling under a city is a delicate business. Creating a void causes the surrounding ground to relax even if a stiff lining support is installed very quickly. These ground movements can result in settlement of buildings, or distortion of other tunnels already in the ground. This risk is managed by predicting the ground movements as accurately as possible and using construction methods that minimise them. Monitoring and mitigation are carefully controlled.</p>
<p>For me, tunnels are like museums or hospitals – a symbol of human civilisation. To excavate ground that has not been touched for millions of years, to work all the hours of the day and night, to produce a structure that will last for hundreds of years, and to do it all in the service of and with the minimum disruption to the surface humans, is truly quite a feat.</p><img src="https://counter.theconversation.com/content/16982/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Benoît Jones occasionally does consultancy work for consultants, contractors and suppliers of products and equipment for the tunnelling industry. He is a member of the Institution of Civil Engineers, the British Tunnelling Society and the International Tunnelling Association.</span></em></p>
Londoners will be aware that there is a lot of work going on under their feet at the moment. There is the new Crossrail railway with eight subterranean stations, expansion of Tottenham Court Road, Bond…
Benoît Jones, Principal Teaching Fellow and MSc Tunnelling and Underground Space Course Manager, University of Warwick
Licensed as Creative Commons – attribution, no derivatives.