探花直播 of Cambridge - earthquake

Cambridge engineer to co-lead earthquake reconnaissance mission to Turkey

jek67 — Mon, 13 Feb 2023 15:21:39 +0000

Professor Emily So, Director of the Cambridge 探花直播 Centre for Risk in the Built Environment (CURBE) will be co-leading a UK team of engineers, seismologists and geologists on a reconnaissance mission to Turkey, to undertake post-earthquake assessments and uncover the causes of this natural disaster.

Organised by 探花直播Earthquake Engineering Field Investigation Team (EEFIT), Professor So will co-lead the mission alongside Yasemin Didem Aktas from UCL and will work closely to support Turkish colleagues and officials. 探花直播EEFIT is a joint venture between industry and universities, conducting field investigations following major earthquakes.

探花直播earthquake struck south-eastern Turkey and neighbouring Syria on Monday 6 Feb, registering a 7.8 magnitude quake. It is Turkey's worst earthquake since 1939, impacting聽13.4 million people living in the 10 provinces hit by it. At the time of writing, the death toll had climbed to more than 36,000, with the United Nations warning that the final number may double.

探花直播reconnaissance mission will carry out detailed technical evaluations of the performance of structures, foundations, civil engineering works and industrial plants within the affected regions. They will also assess the effectiveness of earthquake protection methods, study disaster management procedures and investigate the socio-economic effects of the earthquake.

Professor Emily So says: 鈥淟ast week鈥檚 earthquake has caused untold damage and suffering for up to 15% of Turkey鈥檚 population. This mission will enable us to observe the damage and the effects of the earthquake first-hand to identify the main lessons that can be learnt. 探花直播EEFIT mission is our opportunity to observe the real performances of buildings and question why they have collapsed and why they have not withstood the earthquake. These lessons are key to help direct future research, and prioritise actions for change.鈥�

Professor So is a chartered civil engineer and Director of the Cambridge 探花直播 Centre for Risk in the Built Environment (CURBE). Her main area of interest is in assessing and managing urban risk and resilience. She has actively engaged with earthquake鈥恆ffected communities in different parts of the world, focusing on applying her work towards making real鈥� world improvements in seismic safety.聽

Saving lives from earthquakes is a priority and motivates her research. Her area of specialty is casualty estimation in earthquake loss modelling and her research has led to improved understanding of the relationship between deaths and injuries following earthquakes.

Recognised as an expert in the field, Professor So sits on the Scientific Advisory Group for Emergencies (SAGE) providing valuable and timely scientific and technical advice to support the UK Government鈥檚 Cabinet Office Briefing Room (COBR).

Professor So is a Fellow and Admissions Tutor for Recruitment at Magdalene College, Director of Studies in Architecture at Magdalene and St Edmund鈥檚 College and a Director of Cambridge Architectural Research Ltd.

Professor Emily So will lead a UK response to uncover the causes of the extensive damage and loss of life

This mission will enable us to observe the damage and the effects of the earthquake first-hand to identify the main lessons that can be learnt...These will be key to help prioritise actions for change.鈥�

Professor Emily So

@Turkey earthquake 鈥� a glimpse of the ECHO assessment" by EU Civil Protection and Humanitarian Aid

Turkey earthquake 鈥� a glimpse of the ECHO assessment

探花直播text in this work is licensed under a Creative Commons Attribution 4.0 International License. Images, including our videos, are Copyright 漏探花直播 of Cambridge and licensors/contributors as identified.聽 All rights reserved. We make our image and video content available in a number of ways 鈥� as here, on our main website under its Terms and conditions, and on a range of channels including social media that permit your use and sharing of our content under their respective Terms.

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Moving a capital city: learning from when the earth moves

lw355 — Tue, 14 Nov 2023 09:03:46 +0000

Indonesia plans to build a new capital city from scratch. Protecting the new city from the effects of earthquakes will be crucial. Here's how researchers are helping.

Scientists 'see' puzzling features deep in Earth鈥檚 interior

cmm201 — Thu, 19 May 2022 09:00:00 +0000

探花直播enigmatic area of rock, which is located almost directly beneath the Hawaiian Islands, is one of several ultra-low velocity zones 鈥� so-called because earthquake waves slow to a crawl as they pass through them.

探花直播research, published in Nature Communications, is the first to reveal the complex internal variability of one of these pockets in detail, shedding light on the landscape of Earth鈥檚 deep interior and the processes operating within it. 聽

鈥淥f all Earth鈥檚 deep interior features, these are the most fascinating and complex. We鈥檝e now got the first solid evidence to show their internal structure - it鈥檚 a real milestone in deep earth seismology,鈥� said lead author Zhi Li, PhD student at Cambridge鈥檚 Department of Earth Sciences.

Earth鈥檚 interior is layered like an onion: at the centre sits the iron-nickel core, surrounded by a thick layer known as the mantle, and on top of that a thin outer shell 鈥� the crust we live on. Although the mantle is solid rock, it is hot enough to flow extremely slowly. These internal convection currents feed heat to the surface, driving the movement of tectonic plates and fuelling volcanic eruptions. 聽

Scientists use seismic waves from earthquakes to 'see' beneath Earth鈥檚 surface 鈥� the echoes and shadows of these waves reveal radar-like images of deep interior topography. But, until recently, 'images'聽of the structures at the core-mantle boundary, an area of key interest for studying our planet鈥檚 internal heat flow, have been grainy and difficult to interpret.

探花直播researchers used the latest numerical modelling methods to reveal kilometre-scale structures at the core-mantle boundary. According to co-author Dr Kuangdai Leng, who developed the methods while at the 探花直播 of Oxford, 鈥淲e are really pushing the limits of modern high-performance computing for elastodynamic simulations, taking advantage of wave symmetries unnoticed or unused before.鈥� Leng, who is currently based at the Science and Technology Facilities Council, says that this means they can improve the resolution of the images by an order of magnitude compared to previous work.聽

探花直播researchers observed a 40% reduction in the speed of seismic waves travelling at the base of the ultra-low velocity zone beneath Hawaii. This supports existing proposals that the zone contains much more iron than the surrounding rocks 鈥� meaning it is denser and more sluggish. 鈥淚t鈥檚 possible that this iron-rich material is a remnant of ancient rocks from Earth鈥檚 early history or even that iron might be leaking from the core by an unknown means,鈥� said project lead聽Dr Sanne Cottaar from Cambridge Earth Sciences.

探花直播research could also help scientists understand what sits beneath and gives rise to volcanic chains like the Hawaiian Islands. Scientists have started to notice a correlation between the location of the descriptively-named hotspot volcanoes, which include Hawaii and Iceland, and the ultra-low velocity zones at the base of the mantle. 探花直播origin of hotspot volcanoes has been debated, but the most popular theory suggests that plume-like structures bring hot mantle material all the way from the core-mantle boundary to the surface.

With images of the ultra-low velocity zone beneath Hawaii now in hand, the team can also gather rare physical evidence from what is likely the root of the plume feeding Hawaii. Their observation of dense, iron-rich rock beneath Hawaii would support surface observations. 鈥淏asalts erupting from Hawaii have anomalous isotope signatures which could either point to either an early-Earth origin or core leaking, it means some of this dense material piled up at the base must be dragged to the surface,鈥� said Cottaar.

More of the core-mantle boundary now needs to be imaged to understand if all surface hotspots have a pocket of dense material at the base. Where and how the core-mantle boundary can be targeted does depend on where earthquakes occur, and where seismometers are installed to record the waves. 聽

探花直播team鈥檚 observations add to a growing body of evidence that Earth鈥檚 deep interior is just as variable as its surface. 鈥淭hese low-velocity zones are one of the most intricate features we see at extreme depths 鈥� if we expand our search, we are likely to see ever-increasing levels of complexity, both structural and chemical, at the core-mantle boundary,鈥� said Li.

They now plan to apply their techniques to enhance the resolution of imaging of other pockets at the core-mantle boundary, as well as mapping new zones. Eventually they hope to map the geological landscape across the core-mantle boundary and understand its relationship with the dynamics and evolutionary history of our planet.

Reference:
Zhi Li, Kuangdai Leng, Jennifer Jenkins, Sanne Cottaar.聽'Kilometer-scale structure on the core鈥搈antle boundary near Hawaii.' Nature Communications (2022), DOI: 10.1038/s41467-022-30502-5

New research led by the 探花直播 of Cambridge is the first to obtain a detailed 'image'聽of an unusual pocket of rock at the boundary layer with Earth鈥檚 core, some three thousand kilometres beneath the surface.

Of all Earth鈥檚 deep interior features, these are the most fascinating and complex

Zhi Li

gnuckx

Etna volcano eruption, 12 January 2011

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Rock crystals from the deep give microscopic clues to earthquake ground movements

cmm201 — Thu, 24 Jun 2021 10:27:18 +0000

探花直播stresses resulting from these defects 鈥� which are small enough to disrupt the atomic building blocks of a crystal 鈥� can transform how hot rocks beneath Earth鈥檚 crust move and in turn transfer stress back to Earth鈥檚 surface, starting the countdown to the next earthquake.聽

探花直播new study, published in Nature Communications, is the first to map out the crystal defects and surrounding force fields in detail. 鈥淭hey鈥檙e so tiny that we鈥檝e only been able to observe them with the latest microscopy techniques,鈥� said lead author Dr David Wallis from Cambridge's Department of聽Earth Sciences, 鈥淏ut it鈥檚 clear that they can significantly influence how deep rocks move, and even govern when and where the next earthquake will happen.鈥�

By understanding how these crystal defects influence rocks in the Earth鈥檚 upper mantle, scientists can better interpret measurements of ground motions following earthquakes, which give vital information on where stress is building up - and in turn where future earthquakes may occur.

Earthquakes happen when pieces of Earth鈥檚 crust suddenly slip past each other along fault lines, releasing stored-up energy which propagates through the Earth and causes it to shake. This movement is generally a response to the build-up of tectonic forces in the Earth鈥檚 crust, causing the surface to buckle and eventually rupture in the form of an earthquake.

Their work reveals that the way Earth鈥檚 surface settles after an earthquake, and stores stress prior to a repeat event, can ultimately be traced to tiny defects in rock crystals from the deep.

鈥淚f you can understand how fast these deep rocks can flow, and how long it will take to transfer stress between different areas across a fault zone, then we might be able to get better predictions of when and where the next earthquake will strike,鈥� said Wallis.

探花直播team subjected olivine crystals 鈥� the most common component of the upper mantle -- to a range of pressures and temperatures in order to replicate conditions of up to 100 km beneath Earth鈥檚 surface, where the rocks are so hot (roughly 1250^oC) they move like syrup.

Wallis likens their experiments to a blacksmith working with hot metal 鈥� at the highest temperatures, their samples were glowing white-hot and pliable.

They observed the distorted crystal structures using a high-resolution form of electron microscopy, called electron backscatter diffraction, which Wallis has pioneered on geological materials.

Their results shed light on how hot rocks in the upper mantle can mysteriously morph from flowing almost like syrup immediately after an earthquake to becoming thick and sluggish as time passes.

This change in thickness -- or viscosity 鈥� transfers stress back to the cold and brittle rocks in the crust above, where it builds up 鈥� until the next earthquake strikes.

探花直播reason for this switch in behaviour has remained an open question, 鈥淲e鈥檝e known that microscale processes are a key factor controlling earthquakes for a while, but it鈥檚 been difficult to observe these tiny features in enough detail,鈥� said Wallis. 鈥淭hanks to a state-of-the-art microscopy technique, we鈥檝e been able to look into the crystal framework of hot, deep rocks and track down how important these miniscule defects really are鈥�.

Wallis and co-authors show that irregularities in the crystals become increasingly tangled over time; jostling for space due to their competing force fields 鈥� and it鈥檚 this process that causes the rocks to become more viscous.

Until now it had been thought that this increase in viscosity was because of the competing push and pull of crystals against each other, rather than being caused by microscopic defects and their stress fields inside the crystals themselves.

探花直播team hope to apply their work to improving seismic hazard maps, which are often used in tectonically active areas like southern California to estimate where the next earthquake will occur. Current models, which are usually based on where earthquakes have struck in the past, and where stress must therefore be building up, only take into account the more immediate changes across a fault zone and do not consider gradual stress changes in rocks flowing deep within the Earth.

Working with colleagues at Utrecht 探花直播, Wallis also plans to apply their new lab constraints to models of ground movements following the hazardous 2004 earthquake which struck Indonesia, and the 2011 Japan quake 鈥� both of which triggered tsunamis and lead to the loss of tens of thousands of lives.

聽

Reference:
David Wallis et al.聽'Dislocation interactions in olivine control postseismic creep of the upper mantle.'聽Nature Communications (2021). DOI: 10.1038/s41467-021-23633-8

Microscopic imperfections in rock crystals deep beneath Earth鈥檚 surface play a deciding factor in how the ground slowly moves and resets in the aftermath of major earthquakes, says new research involving the 探花直播 of Cambridge.

James St John

Chunks of exotic green rocks from the mantle erupted from the San Carlos Volcanic Field, Arizona

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Machine learning used to predict earthquakes in a lab setting

sc604 — Mon, 23 Oct 2017 00:28:01 +0000

探花直播team, from the 探花直播 of Cambridge, Los Alamos National Laboratory and Boston 探花直播, identified a hidden signal leading up to earthquakes聽and used this 鈥榝ingerprint鈥� to train a machine learning algorithm to predict future earthquakes. Their results, which could also be applied to avalanches, landslides and more, are reported in the journal Geophysical Review Letters.

For geoscientists, predicting the timing and magnitude of an earthquake is a fundamental goal. Generally speaking, pinpointing where an earthquake will occur is fairly straightforward: if an earthquake has struck a particular place before, the chances are it will strike there again. 探花直播questions that have challenged scientists for decades are how to pinpoint when an earthquake will occur, and how severe it will be. Over the past 15 years, advances in instrument precision have been made, but a reliable earthquake prediction technique has not yet been developed.

As part of a project searching for ways to use machine learning techniques to make gallium nitride (GaN) LEDs more efficient, the study鈥檚 first author, Bertrand Rouet-Leduc, who was then a PhD student at Cambridge, moved to Los Alamos National Laboratory in New Mexico to start a collaboration on machine learning in materials science between Cambridge 探花直播 and Los Alamos. From there the team started helping the Los Alamos Geophysics group on machine learning questions.

探花直播team at Los Alamos, led by Paul Johnson, studies the interactions among earthquakes, precursor quakes (often very small earth movements) and faults, with the hope of developing a method to predict earthquakes. Using a lab-based system that mimics real earthquakes, the researchers used machine learning techniques to analyse the acoustic signals coming from the 鈥榝ault鈥� as it moved and search for patterns.

探花直播laboratory apparatus uses steel blocks to closely mimic the physical forces at work in a real earthquake, and also records the seismic signals and sounds that are emitted. Machine learning is then used to find the relationship between the acoustic signal coming from the fault and how close it is to failing.

探花直播machine learning algorithm was able to identify a particular pattern in the sound, previously thought to be nothing more than noise, which occurs long before an earthquake. 探花直播characteristics of this sound pattern can be used to give a precise estimate (within a few percent) of the stress on the fault (that is, how much force is it under) and to estimate the time remaining before failure, which gets more and more precise as failure approaches. 探花直播team now thinks that this sound pattern is a direct measure of the elastic energy that is in the system at a given time.

鈥淭his is the first time that machine learning has been used to analyse acoustic data to predict when an earthquake will occur, long before it does, so that plenty of warning time can be given 鈥� it鈥檚 incredible what machine learning can do,鈥� said co-author Professor Sir Colin Humphreys of Cambridge鈥檚 Department of Materials Science & Metallurgy, whose main area of research is energy-efficient and cost-effective LEDs. Humphreys was Rouet-Leduc鈥檚 supervisor when he was a PhD student at Cambridge.

鈥淢achine learning enables the analysis of datasets too large to handle manually and looks at data in an unbiased way that enables discoveries to be made,鈥� said Rouet-Leduc.

Although the researchers caution that there are multiple differences between a lab-based experiment and a real earthquake, they hope to progressively scale up their approach by applying it to real systems which most resemble their lab system. One such site is in California along the San Andreas Fault, where characteristic small repeating earthquakes are similar to those in the lab-based earthquake simulator. Progress is also being made on the Cascadia fault in the Pacific Northwest of the United States and British Columbia, Canada, where repeating slow earthquakes that occur over weeks or months are also very similar to laboratory earthquakes.

鈥淲e鈥檙e at a point where huge advances in instrumentation, machine learning, faster computers and our ability to handle massive data sets could bring about huge advances in earthquake science,鈥� said Rouet-Leduc.

Reference:
Bertrand Rouet-Leduc et al. 鈥�Machine Learning Predicts Laboratory Earthquakes.鈥� Geophysical Research Letters (2017). DOI: 10.1002/2017GL074677

聽

A group of researchers from the UK and the US have used machine learning techniques to successfully predict earthquakes. Although their work was performed in a laboratory setting, the experiment closely mimics real-life conditions, and the results could be used to predict the timing of a real earthquake.聽

This is the first time that machine learning has been used to analyse acoustic data to predict when an earthquake will occur.

Colin Humphreys

United Nations Development Programme

Haiti Earthquake

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'Extreme sleepover #18' 鈥� rebuilding earthquake-shattered Christchurch

lw355 — Thu, 22 Sep 2016 07:49:39 +0000

At 2.30am I sit with my laptop feeling helpless as I watch video footage of a dust cloud rising around the crumbling cathedral in the city square. An earthquake has hit my hometown of Christchurch, New Zealand, and all I can do is scan the internet for snippets of information. Mild panic rises in my stomach, I have had no news of my family.

I had been woken by a text from a friend but there were no other messages, emails or missed calls. Finally I reach my mum on her mobile phone as she emerges from a central city building. She had spent three hours stuck on the tenth floor with no power, an incessant fire alarm and no safe way out. Firemen arrived to help her and stranded colleagues negotiate the dark internal stairwells that had pulled away from the walls, with water pouring from broken water pipes above.

We speak only briefly to keep the airways free for others, but I at least learn that my immediate family are okay. After the boost of adrenaline, I can鈥檛 sleep. A few hours later, feeling a little lost, I set off for rowing training as life around me in Cambridge surreally continues as normal.

That was 2011 and at the time I was completing an MPhil degree in the Engineering Department. Following my degree, I returned to New Zealand to work on the reconstruction of Christchurch, feeling motivated that as an engineer I could contribute towards rebuilding the city.

I experienced the aftershocks (which numbered in the thousands) and became adept at estimating the epicentre through the sound and feel of the shaking. Life was fairly normal living on the western side of the city where there was minimal damage. However, I worked in badly damaged areas in the east, where houses had tilted on their foundations and the roads were rough and potholed from liquefaction damage.

Partway through the year I was offered funding for a PhD back in Cambridge. I saw an opportunity to research the reconstruction as it progressed and to capture insights as to why and how decisions were made. I believed I could continue to make a meaningful contribution, albeit shifting to the role of observer rather than as a direct participant in the recovery process.

My research involved returning to Christchurch for fieldwork each year, interviewing engineers, executives, political leaders and other professionals involved in planning and implementing the reconstruction.

探花直播initial shift from practitioner to researcher was a personal challenge. I felt I had to prove my relevance to the rebuild effort to those dealing with the stresses and challenges of the process every day. However, my fears gradually dissipated 鈥� I was welcomed back and people were happy to spend time with me to reflect on their experiences. Sometimes it was also a chance to vent their frustrations.

I had initially considered conducting multiple case studies around the world, but soon realised the value of a longer-term study in Christchurch to capture changes over time. Also, as a PhD student with limited time and budget, it made sense to work in a region where I had a good understanding of the politics and the culture and a connection to people through shared experience.

Securing interviews with critical decision makers involved planning (sometimes years in the process) and a little luck. During field visits I had an allocated desk at one of the major recovery organisations and attended community and industry events. This meant I could immerse myself in recovery discussions and I had opportunities to join meetings simply because I was in the office at the right time.

On my final visit I met with the central government minister in charge of the recovery. We discussed major decisions made by the government in response to the earthquakes. This included the establishment of new legislation, the creation of new organisations to lead the recovery and the red zoning of residential land, where approximately 8,000 residential properties now sit empty as their future is debated.

One of the many challenges of the recovery was the need to create new organisations to lead the process and to interpret ambiguous policy statements regarding funding commitments. Although there were long processes of negotiation (establishing clear funding arrangements, for example, took years), a pre-defined, prescriptive approach could have been equally unsatisfactory.

Five years into the recovery, there is a lingering question over how to be better prepared in the future. There is a need to create policies that provide both appropriate clear guidance and flexibility to respond to specific circumstances. This remains the subject of much debate in New Zealand. Despite the country鈥檚 relatively advanced system for emergency management, it was caught off-guard by a large earthquake in Christchurch.

My research has shown that while post-disaster reconstruction may be considered an opportunity to rebuild more resilient infrastructure, many potential opportunities may be excluded. Contributing factors include financial constraints, limits in scope of organisations involved and the inherent challenge of introducing change to communities, particularly in the time-constrained context of recovery.

With a better understanding of such factors, we can gain better insight into the effectiveness of different decisions and subsequent pathways for recovery. Unfortunately, with natural disasters like earthquakes, there is no prevention; there is only preparation for the next time disaster strikes.

Kristen was primarily funded through a Cambridge International Scholarship from the Cambridge Trusts. She also received small grants from the Earthquake Commission in New Zealand, the Department of Engineering, Corpus Christi College and the Cambridge Philosophical Society. Her PhD was supervised by Professor Peter Guthrie.

Kristen MacAskill describes how an earthquake in her hometown served to influence her career as an engineer.

Houses had tilted on their foundations and the roads were rough and potholed from liquefaction damage

Kristen MacAskill

Martin Luff

A badly damaged house in North New Brighton, Christchurch, New Zealand

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Earthquake rocks Afghanistan and Pakistan 鈥� an area prone to magnitude 7 quakes

Anonymous — Tue, 27 Oct 2015 12:35:31 +0000

A devastating earthquake struck the Hindu Kush region of north-east Afghanistan just after lunchtime on October 26, rocking communities as far away as Tajikistan, Pakistan and even India. A devastating earthquake struck the Hindu Kush region of north-east Afghanistan just after lunchtime on October 26, rocking communities as far away as Tajikistan, Pakistan and even India.

探花直播strong quake, estimated at magnitude 7.5 by the US Geological Survey (USGS), had its origins more than 200km deep beneath Earth鈥檚 surface, and was felt as strong shaking across a very wide area. Casualties have been reported from across the region, with widespread landslips causing potential further damage to infrastructure.

So far it has been reported that 150 people have died, but this number is likely to rise.

探花直播quake is the second large shake to hit the Alpine-Himalayan earthquake belt this year, following the one that devastated Nepal in April. A region stretching from the Mediterranean through Anatolia, Iran and Central Asia into the mountains of South-East Asia, the Alpine-Himalayan belt is the home of around a fifth of the world鈥檚 largest earthquakes.

聽

Tectonic plates collide. LennyWikipedia~commonswiki, CC BY-SA

聽

探花直播earthquake was driven by collision between the Eurasian tectonic plate to the north and the Indian plate to the south. 探花直播area marks the scar of the closure of an ancient ocean, the Thethys, which once separated the continents of Gondwana, including most of the landmasses in today鈥檚 southern hemisphere, and Laurasia, made up of most of the countries that are today in the northern hemisphere.

探花直播Hindu Kush has experienced many such earthquakes before today, and this latest appears to follow closely the pattern of those of the past. Preliminary analysis by the USGS indicates that it was caused by a deep fault in which rocks thrust past each other instantaneously. They point out that seven earthquakes of magnitude 7 or more have hit within 250km of the current earthquake over the past century. Most recently the magnitude 7.4 earthquake, some 20km west of the latest event, killed over 150 people in March 2002.

This type of deep fault, a near-vertical a thrust fault, is a process that has previously been associated with the tearing off of sections of ancient ocean floor sinking into the Earth鈥檚 mantle beneath today鈥檚 continent. Researchers have previously suggested that earthquakes in the Hindu Kush can be caused by the break off of strips of such slabs, stretching and tearing free, on geological time scales, as they fall deep into the mantle.

Whatever the geological triggers for the quake, grieving communities will now be gathering themselves together and guarding against the inevitable aftershocks. With increased understanding of the risks that Earth poses along this seismic belt, it is important to be aware and prepare for future large earthquakes. If buildings are not to be destroyed time and again, it is important to adopt and adhere to construction and planning codes. A key step in promoting legal enforcement is educating the community about the risks, as well as how to respond as safely as possible during an earthquake.

Efforts such as the 鈥�Earthquakes without Frontiers鈥� continue to highlight the risks of earthquakes, and have drawn attention to the tectonic forces that stand poised to strike along Tethys鈥� former shores.

Simon Redfern, Professor in Earth Sciences, 探花直播 of Cambridge

This article was originally published on 探花直播Conversation. Read the original article.

探花直播opinions expressed in this article are those of the individual author(s) and do not represent the views of the 探花直播 of Cambridge.

Professor Simon Redfern (Department of Earth Sciences) discusses the devastating earthquake that struck Afghanistan on October 26 and the geological triggers that caused it.

Wikimedia Commons

Topography of Hindu Kush.

探花直播text in this work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. Images, including our videos, are Copyright 漏探花直播 of Cambridge and licensors/contributors as identified. All rights reserved. We make our image and video content available in a number of ways 鈥� as here, on our main website under its Terms and conditions, and on a range of channels including social media that permit your use and sharing of our content under their respective Terms.

For image use please see separate credits above.

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Earthquakes without frontiers

sc604 — Mon, 26 Oct 2015 13:31:11 +0000

探花直播Ganges is India鈥檚 most iconic river, flowing from the Himalaya to the Bay of Bengal, and its massive river basin is one of the most fertile and densely populated regions in the world. 探花直播Ganges flows through 29 cities with a population over 100,000, 23 cities with a population between 50,000 and 100,000, and close to 50 towns.

But someday 鈥� perhaps tomorrow or perhaps in 100 years 鈥� a massive earthquake will hit the region, and the consequences could be catastrophic: as many as a million lives in the Ganges river basin could be at risk, primarily because buildings have not been constructed to be earthquake resilient, despite the fact that the relevant building codes are in place.

Of course, earthquakes don鈥檛 respect borders, and India is not alone in being at risk due to poorly constructed buildings. Northern India lies in the Alpine鈥揌imalayan earthquake belt, which stretches from the Mediterranean to the Pacific. It is the second-most seismically active region in the world, and responsible for around 20% of the world鈥檚 largest earthquakes. 探花直播belt is being created by ongoing plate tectonics: as the African, Arabian and Indian plates continue to move northwards, they collide with the Eurasian plate.

探花直播earthquake belt includes the most famous of the great trade routes, the Silk Road, which follows the edges of deserts and mountains, and high plateaus like Tibet. 探花直播landscape of the Silk Road has been shaped by earthquakes over millions of years: forcing mountains upwards and making life in the desert possible by controlling where water comes to the surface.

As the earthquake faults grind rocks together they make an impermeable clay, which often forces water to the surface along spring lines, determining where people live. To the casual observer, it seems as if the major earthquakes in this part of the world often seem to 鈥榯arget鈥� towns and cities but, in reality, people are often simply living where the water is, which is also where earthquakes happen.

Between 2 and 2.5 million people have died in earthquakes since 1900. Approximately two thirds of those deaths occurred in earthquakes in the continental interiors 鈥� places like northern India. Over that time, advances in the scientific understanding of earthquakes have been translated into impressive resilience in places where the hazard is well understood, which are mainly on the edges of the oceans. Comparable advances have not, however, taken place in most parts of the continental interiors, where the hazard is still much less well identified and poorly understood.

鈥淓arthquake science has progressed so that we鈥檙e now much better at recognising the signals in the landscape that tell us whether a particular place is dangerous,鈥� says Professor James Jackson, Head of Cambridge鈥檚 Department of Earth Sciences. 鈥淲e can鈥檛 tell you exactly when an earthquake is going to happen, but we can say it will happen, not least because it鈥檚 happened before. If it鈥檚 happened before, it will happen again. What we can do, however, is to understand earthquakes better and use that knowledge to help make buildings safer.鈥�

Four years ago, with funding from the Natural Environment Research Council, Jackson and colleagues from other universities in the UK established Earthquakes Without Frontiers (EWF), an international partnership bringing together earthquake scientists from across the great earthquake belt, from China to Italy, in order to share expertise. 鈥淏ut it soon became clear that the project was about much more than earthquake science, and the real issue was how to translate science into effective policy, which requires an understanding of the social context in which people live,鈥� says Jackson.

With additional funding from the Economic and Social Research Council, EWF expanded to include social science and policy dimensions. 探花直播project, which runs until 2017, has three overarching objectives: to increase knowledge of earthquake hazards across the region; to establish greater resiliency against these hazards; and to establish a well-networked interdisciplinary partnership to support local earthquake scientists. Within Asia, there are more than 50 national level stakeholders who are working with EWF on earthquake risk reduction.

Across much of the earthquake belt, people live in large cities, mostly in poorly built apartment blocks and buildings that have not been designed to withstand earthquakes. Large cities such as Tehran, Almaty and Bishkek have all been destroyed multiple times by earthquakes, and it鈥檚 only a matter of time before the next one hits. 探花直播problem that EWF faces is convincing the public and policy makers of the importance of making towns and cities more earthquake resilient.

鈥淚n these big cities, everyday life is difficult enough: they鈥檙e very congested, they have huge problems with traffic, air quality, water quality, food supply and poverty,鈥� explains Jackson. 鈥淎nd quite understandably, the risk of an earthquake seems quite remote compared to daily worries. But that doesn鈥檛 make the threat go away.鈥�

鈥淲e face two main problems: the first is that there is a lack of awareness of the fact that seismologists cannot predict earthquakes 鈥� it鈥檚 just not something we are able to do or will be able to do,鈥� says Dr Supriyo Mitra of the Indian Institute of Science Education and Research Kolkata. Mitra obtained his PhD at Cambridge, and is now one of the key Indian academic collaborators on the project, primarily working in Indian-administered Kashmir. 鈥� 探花直播other problem is that there is a lot of resistance to making buildings safe. It is an additional cost, but it鈥檚 a necessity and we need to get that across to people.鈥�

Perhaps the most important change that can be made to increase earthquake resilience in these areas is the enforcement of building codes. 探花直播building codes in Los Angeles and Tehran are similar, but the difference is that in Los Angeles, most buildings are constructed according to those codes, while in Tehran most are not, so as a result, Los Angeles is highly resilient to earthquakes, while Tehran remains very vulnerable.

鈥淓nforcement comes not just from legal enforcement, but education,鈥� adds Jackson. 鈥淧eople are really starting to realise that this is important. And once you educate the public, it rises up the agenda because the public insists that it does.

鈥淭here are going to be around a billion new homes built across Asia over the next 10 years 鈥� let鈥檚 build them so they are safe.鈥�

探花直播Alpine鈥揌imalayan belt, which stretches from the Mediterranean to the Pacific, is one of the world鈥檚 most seismically active regions. Now, a combination of earth science, social science and education is being used to help the region become more resilient to earthquakes, protecting lives and property.

We can鈥檛 tell you exactly when an earthquake is going to happen, but we can say it will happen, not least because it鈥檚 happened before. If it鈥檚 happened before, it will happen again.

James Jackson

Timothy Smith, U.S. Navy

探花直播city of Muzafarabad, Pakistan lays in ruins after the 2005 Kashmir earthquake that hit the region.

探花直播text in this work is licensed under a Creative Commons Attribution 4.0 International License. For image use please see separate credits above.

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