tag:theconversation.com,2011:/institutions/geoscience-australia-5347/articlesGeoscience Australia2023-05-26T05:45:51Ztag:theconversation.com,2011:article/2058452023-05-26T05:45:51Z2023-05-26T05:45:51ZPicture this: green hydrogen plants next to green steelworks to boost efficiency and kickstart both industries<figure><img src="https://images.theconversation.com/files/528495/original/file-20230526-23-vinqv8.jpg?ixlib=rb-1.1.0&rect=15%2C37%2C4987%2C3292&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>The race to net zero is accelerating. Just last week, United States President Joe Biden and Australian Prime Minister Anthony Albanese unveiled a <a href="https://www.pm.gov.au/media/australia-united-states-climate-critical-minerals-and-clean-energy-transformation-compact">climate pact</a> to boost cooperation. The move signifies Australia is becoming a global leader in the renewable energy roll-out and critical mineral supply. </p>
<p>Australia’s rich iron ore deposits and cheap solar offer yet another way we can lead. If we locate green hydrogen plants near green steel facilities, we can shift the highly polluting steel industry away from fossil fuels. </p>
<p>Our <a href="https://www.sciencedirect.com/science/article/pii/S0360319923022930">new research</a> shows co-locating plants in sun-rich, iron-rich places like Western Australia’s Pilbara and South Australia’s Eyre Peninsula can help overcome the “first mover problem” for green hydrogen: you can’t have a hydrogen industry without buyers for it and can’t have buyers without hydrogen.</p>
<p>How would it work? Cheap solar power would be used to crack water into hydrogen and oxygen. This green hydrogen would be piped a short distance to a green steel plant, which uses hydrogen and electricity to produce iron from the ore, and then an electric arc furnace to smelt steel.</p>
<p>As we grapple with ways to decarbonise the steel sector, which uses 8% of the world’s energy and produces 7% of all energy-related carbon emissions, we should urgently look for opportunities like this. As a bonus, cheap power from solar and wind could make Australian-made iron and steel more competitive globally.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/528491/original/file-20230526-7168-e5g7ll.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="steelmaking" src="https://images.theconversation.com/files/528491/original/file-20230526-7168-e5g7ll.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/528491/original/file-20230526-7168-e5g7ll.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/528491/original/file-20230526-7168-e5g7ll.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/528491/original/file-20230526-7168-e5g7ll.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/528491/original/file-20230526-7168-e5g7ll.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/528491/original/file-20230526-7168-e5g7ll.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/528491/original/file-20230526-7168-e5g7ll.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>
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<span class="caption">Making iron and steel is enormously energy intensive.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
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<h2>Why is Australia so well placed?</h2>
<p>We’re the world’s largest iron ore exporter. Under our red dirt lies an estimated 56 billion tonnes of iron ore, as of 2021. Export earnings reached A$133 billion in 2021–22. We also profit from the current emissions-heavy way of making steel, by exporting $72 billion worth of metallurgical coal. </p>
<p>Australia’s potential as a green hydrogen provider is often promoted. This year’s federal budget allocated $2 billion to <a href="https://theconversation.com/green-hydrogen-funding-is-a-step-forward-but-a-step-doesnt-win-the-race-205390">help make</a> it a reality. But our distance from the rest of the world makes pipelines prohibitively expensive, and shipping hydrogen is difficult. </p>
<hr>
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<strong>
Read more:
<a href="https://theconversation.com/cooperation-with-the-us-could-drive-australias-clean-energy-shift-but-we-must-act-fast-206199">Cooperation with the US could drive Australia’s clean energy shift – but we must act fast</a>
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<p>One solution is to use it here. Green hydrogen could make it possible to onshore more iron and steel production. </p>
<p>Clean steelmaking will bring major change to our iron ore exports if other countries take it up. Traditionally, 96% of our exports are the most common type of ore, hematite. But this is currently not suited to green steelmaking. </p>
<p>By contrast, magnetite ore only accounts for 4% of exports but can be used in hydrogen-based green steelmaking. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/528497/original/file-20230526-15-gywnqa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="magnetite" src="https://images.theconversation.com/files/528497/original/file-20230526-15-gywnqa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/528497/original/file-20230526-15-gywnqa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/528497/original/file-20230526-15-gywnqa.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/528497/original/file-20230526-15-gywnqa.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/528497/original/file-20230526-15-gywnqa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/528497/original/file-20230526-15-gywnqa.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/528497/original/file-20230526-15-gywnqa.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Right now, magnetite is a tiny part of our iron ore exports - but that could change.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
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<p>Australia has vast reserves of magnetite ore, which previously hasn’t been in as much demand. But these ore bodies will become valuable under the right economic conditions. </p>
<p>And while we can solve steel’s carbon problem with much better recycling of this valuable material, we’ll still need new steel equivalent to <a href="https://www.iea.org/reports/iron-and-steel-technology-roadmap">about 50%</a> of the current rate of production in 2050, due to issues with converting scrap to reusable steel and removing contaminants. </p>
<h2>Where should we co-locate these plants?</h2>
<p>Major iron ore centres in the Pilbara and Eyre Peninsula already have ports, a workforce and other infrastructure. That makes them the logical first choice to co-locate solar, wind and hydrogen with iron and steelmaking. </p>
<p>We modelled what would happen if these sites expanded wind and solar power to make hydrogen and found the cost of green steel could drop substantially to around $900 per tonne by 2030 and $750 per tonne by 2050.</p>
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Read more:
<a href="https://theconversation.com/red-dirt-yellow-sun-green-steel-how-australia-could-benefit-from-a-global-shift-to-emissions-free-steel-179286">Red dirt, yellow sun, green steel: how Australia could benefit from a global shift to emissions-free steel</a>
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<p>By exporting green iron and steel, Australia could boost trade value, reduce global greenhouse emissions, and link our exports with global decarbonisation efforts. Steel will become even more important given it’s so vital to manufacturing solar and wind. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/527344/original/file-20230520-29-gdhla4.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/527344/original/file-20230520-29-gdhla4.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=410&fit=crop&dpr=1 600w, https://images.theconversation.com/files/527344/original/file-20230520-29-gdhla4.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=410&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/527344/original/file-20230520-29-gdhla4.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=410&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/527344/original/file-20230520-29-gdhla4.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=515&fit=crop&dpr=1 754w, https://images.theconversation.com/files/527344/original/file-20230520-29-gdhla4.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=515&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/527344/original/file-20230520-29-gdhla4.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=515&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">There’s a strong correlation between potential hydrogen hubs and current and future iron ore operations.</span>
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</figure>
<p>Our <a href="https://portal.ga.gov.au/persona/heft">recent modelling</a> has found key benefits in linking hydrogen hubs and future iron ore operations. </p>
<p>First, it avoids the problem of transporting hydrogen, which, especially in liquid form, can be expensive and energy-intensive to transport.</p>
<p>And second, co-locating green hydrogen gives an immediate boost to the industry. At present, green hydrogen is at the early stage before increased scale and knowledge drives costs down. </p>
<p>To compete with coking coal, green hydrogen must get cheaper. Part of this will come from falling renewable energy prices, better electrolysers to make hydrogen, and carbon pricing. But part of it will be locating hydrogen production where it can be used. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/528493/original/file-20230526-25-whw6nc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="eyre peninsula map" src="https://images.theconversation.com/files/528493/original/file-20230526-25-whw6nc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/528493/original/file-20230526-25-whw6nc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/528493/original/file-20230526-25-whw6nc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/528493/original/file-20230526-25-whw6nc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/528493/original/file-20230526-25-whw6nc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/528493/original/file-20230526-25-whw6nc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/528493/original/file-20230526-25-whw6nc.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">South Australia’s Eyre Peninsula is one of the best spots to co-locate green steel and hydrogen.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>Choosing a site is the most important consideration. While access to infrastructure and cheap ore are important, the cost of green steel largely depends on low-cost hydrogen and cheap renewables. </p>
<p>Australia’s state and federal governments are backing hydrogen as an industry of the future. To go from paper to reality will require policy incentives, low-interest loans, research and development funding, and investment in infrastructure. </p>
<p>Policies to boost renewable energy and develop the hydrogen economy will create a more conducive environment for green steel production. </p>
<p>If we combine our wealth of solar, hydrogen and iron ore, we can help make global steel production green, and also create the conditions for a green hydrogen export industry. </p>
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<strong>
Read more:
<a href="https://theconversation.com/australias-main-iron-ore-exports-may-not-work-with-green-steelmaking-heres-what-we-must-do-to-prepare-201469">Australia's main iron ore exports may not work with green steelmaking. Here's what we must do to prepare</a>
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<img src="https://counter.theconversation.com/content/205845/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Changlong Wang is currently funded by Geoscience Australia through the Exploring for the Future program. He is affiliated with the Monash Energy Institute at Monash University and Melbourne Climate Futures at the University of Melbourne. Changlong participates in IEA Hydrogen TCP Task 41.</span></em></p><p class="fine-print"><em><span>Stuart Walsh receives funding from Geoscience Australia through the Exploring for the Future program. He is affiliated with the Monash Energy Institute and the Monash Hydrogen Energy Research Node at Monash University. </span></em></p><p class="fine-print"><em><span>Andrew Feitz, Marcus Haynes, and Zhehan Weng do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>If we put green hydrogen plants next to green iron and steelmaking, we can clean up steelmaking and boost the hydrogen industry.Changlong Wang, Research fellow, Monash UniversityAndrew Feitz, Director, Geoscience AustraliaMarcus Haynes, Computational Geoscientist, Geoscience AustraliaStuart Walsh, Senior lecturer, Monash UniversityZhehan Weng, Research scientist, Geoscience AustraliaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1857082022-07-03T19:53:36Z2022-07-03T19:53:36ZNot if, but when: unless Papua New Guinea prepares now, the next big earthquake could wreak havoc in Lae<figure><img src="https://images.theconversation.com/files/471776/original/file-20220630-11-7veu8b.jpeg?ixlib=rb-1.1.0&rect=106%2C98%2C5836%2C3858&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Brendan Esposito/AAP</span></span></figcaption></figure><p>Earthquakes can be especially devastating for developing countries, where competing priorities can stymie resource allocation towards earthquake resilience.</p>
<p>Even in tectonically active areas, where tectonic plates meet and scrape against one another, large earthquakes may not occur often enough to seem like a priority compared to more immediate concerns. That is, until one devastates a populated area, as we’re now seeing with the tragedy <a href="https://www.theguardian.com/world/2022/jun/25/taliban-say-they-will-not-interfere-with-afghanistan-earthquake-aid">in Afghanistan</a>. </p>
<p>Nowhere is this more true than in Papua New Guinea. PNG is situated in one of the most tectonically active areas in the world – one that <a href="https://link.springer.com/article/10.1007/s10518-020-00966-1">experiences</a> more than 100 earthquakes of magnitude five or greater each year.</p>
<p>PNG’s stability and economic development are of great interest to Australia. Yet earthquake scientists know recent development gains could be threatened by earthquakes. </p>
<p>We helped create an updated national seismic hazard map for PNG based on modern earthquake data and knowledge of active faults.</p>
<p>The map was developed in a partnership between Geoscience Australia and the PNG government’s Port Moresby Geophysical Observatory. First published <a href="https://link.springer.com/article/10.1007/s10518-020-00966-1">in 2019</a>, it’s now providing the backbone for our ongoing work into earthquake risk assessment and management in PNG. </p>
<h2>Eyes on Lae</h2>
<p>The high level of earthquake activity in PNG was already recognised in national earthquake hazard maps developed in <a href="https://bulletin.nzsee.org.nz/index.php/bnzsee/article/view/952/927">1982</a>. But the poor-quality data used in these early hazard maps resulted in broad areas of moderately elevated hazard – and did not reflect the very high hazard levels near active faults.</p>
<p>Worryingly, PNG’s current building codes are still based on these outdated maps. Buildings and infrastructure near active faults may be vulnerable to large, local earthquakes – particularly since PNG has adopted “Western” construction materials such as masonry, which can be less resilient than traditional wooden structures.</p>
<p>The latest national seismic hazard map shows a particularly pronounced hazard in Lae, PNG’s second-largest city. Lae sits adjacent to a major active tectonic plate boundary known as the Ramu-Markham fault system.</p>
<p>With a population of more than 100,000, many lives and livelihoods would be threatened by a large earthquake. Lae is also a major economic hub for the country. It has the largest port and is the starting point of the transport artery running through mainland PNG. </p>
<p>Concerns raised by the latest hazard map about Lae’s potential vulnerabilities has led us to initiate the Lae Earthquake Risk Project, involving the University of Technology in Lae and the University of Papua New Guinea in Port Moresby. </p>
<p>Our research goal is to better understand and model what the potential impacts of a Ramu-Markham earthquake may be, and how Lae can boost its resilience in the event of a major earthquake.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/471528/original/file-20220629-18-wj7b12.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/471528/original/file-20220629-18-wj7b12.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/471528/original/file-20220629-18-wj7b12.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/471528/original/file-20220629-18-wj7b12.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/471528/original/file-20220629-18-wj7b12.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/471528/original/file-20220629-18-wj7b12.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/471528/original/file-20220629-18-wj7b12.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">We helped install a seismic sensor in New Britain, Papua New Guinea, in 2019. Similar seismic sensors will be installed in Lae as part of the new project.</span>
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<h2>How could a Ramu-Markham earthquake happen?</h2>
<p>Large earthquakes happen when two tectonic plates move against each other. </p>
<p>In the case of the Ramu-Markham fault system, two plates are converging, or moving towards each other. This movement results in friction along the fault, which builds up stress. An earthquake happens when the built-up stress surpasses the frictional strength along the fault. </p>
<p>While we often think of a geologic fault as a “line”, a major fault system like the Ramu-Markham consists of many segments. Any one of these segments (or a combination) may be active. </p>
<p>Segments are often overlapping, and each has a distinct level of activity. We can record this activity using precise GPS measurements of ground movements, also called “strain”. </p>
<p>Our work started by identifying exactly which segments of the Ramu-Markham fault system are active and accumulating strain energy that might be released in an earthquake. We found the ground movement in this fault system can be explained by activity on a single segment called the Gain fault. </p>
<p>This fault segment is more than 100km long and most of Lae lies within 15km of it. A large earthquake at this distance could cause widespread damage.</p>
<figure class="align-center ">
<img alt="Gain and Bumbu faults highlighted over a Google Maps screenshot of PNG" src="https://images.theconversation.com/files/471685/original/file-20220629-12-7oc2sa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/471685/original/file-20220629-12-7oc2sa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/471685/original/file-20220629-12-7oc2sa.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/471685/original/file-20220629-12-7oc2sa.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/471685/original/file-20220629-12-7oc2sa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/471685/original/file-20220629-12-7oc2sa.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/471685/original/file-20220629-12-7oc2sa.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">The Gain and Bumbu faults are two parallel segments of the Ramu-Markham fault system that pass close to Lae.</span>
<span class="attribution"><span class="source">Author provided/Google Maps</span></span>
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</figure>
<h2>The Bumbu fault</h2>
<p>Although GPS measurements of ground movement are consistent with activity being confined to the Gain fault only, this may not be the only way to explain the data. </p>
<p>The Bumbu fault is another segment of the Ramu-Markham fault system, further south, that cuts through Lae’s CBD. If it’s active, it is of potentially greater concern than the Gain fault.</p>
<p><a href="http://star.gsd.spc.int/star_abstracts/2001_MR0445.pdf">Studies</a> from the 1990s on the geology of Lae’s urban centre suggest a “major tectonic event” happened about 250 years ago, possibly on the Bumbu fault, which changed the course of the Bumbu River flowing through Lae today.</p>
<p>Although this event was prior to European contact, it’s supported by local oral histories and other analyses of elevation data taken from around Lae. Questions remain over whether it was a single major event, or a series of smaller events over an extended period.</p>
<p>In either case, being able to verify activity on the Bumbu fault would raise Lae’s earthquake risk to a new level.</p>
<h2>Future work</h2>
<p>The Lae Earthquake Risk Project is ongoing. In addition to more GPS measurements of ground motion, it will involve setting up earthquake-monitoring stations in Lae, and advanced satellite-based radar analysis. The latter should provide a much more detailed picture of which fault segments are active.</p>
<p>Once we know which active segments can produce earthquakes, we can begin to estimate the intensity of shaking these earthquakes may cause in Lae – and what effects they may have on the city’s built environment. </p>
<p>This will hopefully provide specific guidance for constructing new buildings in Lae, and strengthening existing ones. These are the most important steps that can be taken to reduce the impact of future earthquakes.</p>
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Read more:
<a href="https://theconversation.com/australia-is-no-stranger-to-earthquakes-yet-our-planning-polices-have-not-adapted-168470">Australia is no stranger to earthquakes, yet our planning polices have not adapted</a>
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<img src="https://counter.theconversation.com/content/185708/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Phil Cummins works for Geoscience Australia. The National Earthquake Hazard Assessment of PNG and Lae Earthquake Risk projects are funded by the Department of Foreign Affairs and Trade (DFAT).</span></em></p><p class="fine-print"><em><span>Hadi Ghasemi works for Geoscience Australia. The National Earthquake Hazard Assessment of PNG and Lae Earthquake Risk Assessment projects are funded by the Department of Foreign Affairs and Trade (DFAT).</span></em></p>Oral histories talk about a major tectonic event 250 years ago, which changed the course of a river flowing through Lae today.Phil R. Cummins, Professor, Geoscience AustraliaHadi Ghasemi, Senior Seismologist, Geoscience AustraliaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1684802021-09-23T01:53:45Z2021-09-23T01:53:45ZWe may never be able to predict earthquakes – but we can already know enough to be prepared<p>Yesterday’s earthquake in eastern Victoria shook the ground for hundreds of kilometres around and damaged buildings as far away as Melbourne – and took many people by surprise.</p>
<p>While Australia doesn’t compare with seismic hotspots like New Zealand and Japan, relatively small quakes are expected, with Geoscience Australia’s <a href="https://earthquakes.ga.gov.au/">quake tracker</a> listing more than a dozen in the past week alone.</p>
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Read more:
<a href="https://theconversation.com/melbourne-earthquake-what-exactly-happened-and-whats-the-best-way-to-stay-safe-from-aftershocks-168467">Melbourne earthquake: what exactly happened, and what's the best way to stay safe from aftershocks?</a>
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<p>Even though earthquakes happen all the time, we still can’t predict when the next one will strike, or where, or how big it will be. Unfortunately, we may never be able to make that kind of prediction.</p>
<p>But we can estimate the likelihood of future quakes - and often, that’s enough to make sure our cities are prepared to cope with them.</p>
<h2>Why we can’t predict earthquakes</h2>
<p>Earthquakes are caused by sudden slips or ruptures in the rock beneath our feet, driven by the movement of the enormous tectonic plates that make up the Earth’s crust.</p>
<p>The exact timing and location of one of these slips are impossible for us to know in advance. Nobody has ever found a reliable and repeatable indicator that a quake is about to happen. We would need a highly detailed model of all the rock everywhere inside the Earth and an understanding of how it responds to tectonic stress to even stand a chance of predicting an earthquake. </p>
<p>However, suppose we understand the large forces driving the tectonic plates and the current level of earthquake activity, and we also study where faults have ruptured in the past. In that case, we can estimate the likelihood that different types of earthquakes might occur in the future. </p>
<h2>What we can predict</h2>
<p>To calculate the probability of future earthquakes, we look at the seismic activity measured since the development of seismometers about 100 years ago and knowledge of earlier earthquakes from the historical record, and combine these with information about the faults in the Earth’s crust where quakes can occur.</p>
<p>Australia has relatively little seismic activity, but we know there are hundreds of small faults beneath the Australian landmass. These are places where pressure created by the movement of tectonic plates can cause fault rupture or “slip”, which we experience as earthquakes that generate seismic waves and ground shaking. </p>
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<a href="https://images.theconversation.com/files/422585/original/file-20210922-14-lff2km.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/422585/original/file-20210922-14-lff2km.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/422585/original/file-20210922-14-lff2km.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=336&fit=crop&dpr=1 600w, https://images.theconversation.com/files/422585/original/file-20210922-14-lff2km.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=336&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/422585/original/file-20210922-14-lff2km.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=336&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/422585/original/file-20210922-14-lff2km.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=422&fit=crop&dpr=1 754w, https://images.theconversation.com/files/422585/original/file-20210922-14-lff2km.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=422&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/422585/original/file-20210922-14-lff2km.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=422&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Red lines show faults beneath Victoria detected by scientists. The orange circle shows the location of yesterday’s quake.</span>
<span class="attribution"><span class="source">Geoscience Australia</span></span>
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<p>When we discover a fault, from studying earthquakes or looking at aerial imagery, we often send out teams of geologists to dig trenches across the fault to find traces of past, often prehistoric, earthquake rupture. Depending on the type of signature past earthquakes have left in the soil profile, we can estimate the age and extent of fault movement and develop a history of earthquake activity extending hundreds or often thousands of years into the past. </p>
<p>Identifying prehistoric events is important because the time between large earthquakes on major faults may be longer than the instrumental or even historical record. Without knowledge of prehistoric events, we would have to rely exclusively on the relatively short history of instrumentally recorded earthquakes. </p>
<p>This may cause us to miss the big earthquakes that happen very rarely. We know that longer faults, for example, can usually produce bigger quakes – so if even if we haven’t seen a big quake at a long fault, we know it may be possible in future.</p>
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Read more:
<a href="https://theconversation.com/the-earthquake-that-rattled-melbourne-was-among-australias-biggest-in-half-a-century-but-rock-records-reveal-far-mightier-ones-168471">The earthquake that rattled Melbourne was among Australia's biggest in half a century, but rock records reveal far mightier ones</a>
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<p>By combining knowledge of the large earthquake history of nearby faults, and the level of activity of random, smaller earthquakes that may not rupture major faults but occur often enough to be estimated from the instrumental record, we can make a computer model of the likelihood of earthquake occurrence. </p>
<p>For this earthquake occurrence model to be helpful in estimating hazard, we also need to calculate the strength of ground motion generated by each earthquake. This depends strongly on the depth, location, and size of each earthquake. </p>
<p>The ground motion also depends on the properties of rock in the Earth’s crust through which the seismic waves pass, with some rocks absorbing more energy than others. It also depends on the local geology and soil profile near the site of interest, with softer soil leading to stronger ground motion.</p>
<h2>Mapping hazards</h2>
<p>At Geoscience Australia, we have mapped some of these probabilities in the <a href="https://journals.sagepub.com/doi/full/10.1177/8755293019900777">National Seismic Hazard Assessment</a>. For everywhere in Australia, this map shows the ground motions that may be exceeded over the next 50 years, at certain levels of probability. </p>
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<span class="caption">National Seismic Hazard Assessment of Australia map.</span>
<span class="attribution"><span class="source">Geoscience Australia</span>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span>
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<p>This ground motion, usually expressed in terms of a fraction of the acceleration of gravity at the Earth’s surface, is what we call the seismic hazard. Its potential to damage things we value – buildings, for example, or human lives, is what we call “risk”. </p>
<p>From the “risk” point of view, we may not necessarily care if the hazard is high in a place where there are no people, for example, but we may be very concerned if the hazard is high in a big city. </p>
<p>Yesterday’s earthquake is a good example of this: a magnitude 5.9 earthquake in country Victoria is an exciting novelty for most, but the same earthquake occurring in Melbourne would cause huge problems.</p>
<p>Building codes use hazard maps like this to specify how much shaking buildings in an area need to withstand to keep the risk at an acceptable level. Engineers then make sure their buildings are constructed so they won’t fall when they experience the level of ground shaking forecast in the hazard map.</p>
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Read more:
<a href="https://theconversation.com/earthquakes-dont-kill-people-buildings-do-and-those-lovely-decorative-bits-are-the-first-to-fall-168476">Earthquakes don’t kill people; buildings do. And those lovely decorative bits are the first to fall</a>
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<p>However, until the 1989 Newcastle earthquake, no one realised the Australian building code needed to account for earthquake hazard. Many buildings built before this may be vulnerable even to the level of ground shaking forecast by the hazard map. </p>
<p>An earthquake of magnitude 5.9, if it occurs as far from Melbourne as yesterday’s earthquake did, shouldn’t cause significant damage to buildings that follow the current building code. The fact that it did likely means some buildings are built to a lower standard, and indeed we can see from news photos that many of the damaged buildings look like they were built before 1989.</p>
<p>Insurance companies also use hazard maps to determine the likelihood of damaging earthquakes and set their premiums accordingly. </p>
<p>So, while we can’t tell you where the next earthquake will strike or how big it will be, we can quantify the likelihood of ground motion intensity at the location of interest to make sure we’re all ready for it.</p><img src="https://counter.theconversation.com/content/168480/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Phil R. Cummins has received funding from the Australian Research Council. </span></em></p><p class="fine-print"><em><span>Hadi Ghasemi 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>When will the next earthquake come? We don’t know, but that doesn’t mean we can’t get our cities ready.Hadi Ghasemi, Senior Seismologist, Geoscience AustraliaPhil R. Cummins, Professor, Australian National UniversityLicensed as Creative Commons – attribution, no derivatives.