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Geosciences Column: An international effort to understand the hazard risk posed by Nepal’s 2015 Gorkha earthquake

Geosciences Column: An international effort to understand the hazard risk posed by Nepal’s 2015 Gorkha earthquake

Nine months ago the ground in Nepal shook, and it shook hard: on April 25th 2015 the M7.8 Gorkha earthquake struck and was followed by some 250 aftershocks, five of which were greater than M 6.0. The devastation left behind in the aftermath of such an event, and how to coordinate disaster-relief efforts in a vast, mountainous region, is difficult to imagine. Yet, this December at the 2015 AGU Fall Meeting, I came a little closer.

At the meeting I attended the press conference ‘Future Himalayan seismic hazards: Insights from earthquakes in Nepal’. It focused, mainly, on the outcomes of two research papers published in Science on the role that both past and the recent Gorkha earthquakes can play in triggering quake-induce landslides. The findings of the research were covered widely by the media.

I was struck, not only by those findings, but by the personal accounts of the scientists who’d seen the devastation left behind by the earthquake. But more still, what really caught my attention, was the multinational effort and collaboration that went into the research.

Before-and-after photographs of Nepal’s Langtang Valley showing the near-complete destruction of Langtang village due to a massive landslide caused by the 2015 Gorkha earthquake. Photos from 2012 (pre-quake) and 2015 (post-quake) by David Breashears/GlacierWorks. Distributed via NASA Goddard on Flickr.

Before-and-after photographs of Nepal’s Langtang Valley showing the near-complete destruction of Langtang village due to a massive landslide caused by the 2015 Gorkha earthquake. Photos from 2012 (pre-quake) and 2015 (post-quake) by David Breashears/GlacierWorks. Distributed via
NASA Goddard on Flickr. Click to enlarge.

After the press conference I met with Dalia Kirschbaum of the NASA Goddard Space Flight Centre and Dan Shugar of the University of Washington Tacoma, two of the co-authors of the 2015 Gorkha earthquake paper, to discuss this aspect of the research in more detail.

Given the vast geographical area over which the Gorkha earthquake had caused damage, as well as the hard-to-access mountainous terrain, the team used satellite imagery to map earthquake-induced landslides. They also monitored the stability of the region’s moraine dammed glacial lakes, prone to outburst following earthquakes due to the failure of moraine damns.

When a large scale disaster occurs the International Charter on Space and Major Disasters allows for the dedicated collection of space data to contribute towards humanitarian and charitable efforts in areas affected by natural or man-made disasters. Following the Gorkha earthquake, Nepal called for the activation of the charter.

Following Nepal activating the Charter, satellite imagery was provided by NASA, the Japan Aerospace Exploration Agency, the China Space Agency, as well as private organisations such as DigitalGlobe, to name but a few.

This project was “different to what we had seen in the past in terms of international collaboration,” Dalia told me during our conversation.

A group of nine nations, coordinated by the Global Land Ice Measurements from Space, began assessing the imagery provided and mapping the earthquake-induced geohazards, including landslides. In the first instance the data was used to identify potentially hazardous situations where communities and infrastructure might be at risk. This was followed by an effort to build a landslide inventory, which could provide information about the distribution, character, geomorphological, lithological and tectonic controls which govern the occurrence of earthquake triggered landslides.

An international volunteer geohazards team mapped landslides triggered by the 2015 Nepal Gorkha earthquake and its aftershocks. The landslides were mapped using a range of different satellite products. Credit: Landslide mapping team/NASA-GSFC. Distributed via NASA Goddard on Flickr.

An international volunteer geohazards team mapped landslides triggered by the 2015 Nepal Gorkha earthquake and its aftershocks. The landslides were mapped using a range of different satellite products. Credit: Landslide mapping team/NASA-GSFC. Distributed via NASA Goddard on Flickr.

Simultaneously, scientists from the British Geological Survey and Durham University also began to build a database of known geohazards in the region. The data was shared between the two working groups.

“For no other major earthquakes have landslide inventories come from such a diverse range of datasets and organisations,” explained Dalia.

Neither had emergency remote sensing been undertaken so quickly.

I was interested in why the Nepal earthquakes in particular had inspired this, so far unique – but hopefully not the last – diverse international collaboration to better understand earthquake-induced geohazards.

Dan Shugar thinks it was because so many geoscientists have a deep personal connection with Nepal. Durham University scientists, for example, take geology students to the region on an annual field trip.

“Everybody loves Nepal! The nature of the country really lent itself to people wanting to help,” he added.

Field visit identifies light damage at Tsho (lake) Rolpa. Post-earthquake image of Tsho Rolpa appears identical to its appearance shortly before the earthquake. Two areas of fractures —believed formed by the May 12 2015 aftershock— were observed on the engineered part of the end moraine from a helicopter during an inspection undertaken by the U.S. Geological Survey at Tsho Rolpa. Photos from 27 May by Brian Collins/USGS, courtesy of USAID-OFDA (Office of Foreign Disaster Aid). Distributed via NASA Goddard on Flickr.

Field visit identifies light damage at Tsho (lake) Rolpa. Post-earthquake image of Tsho Rolpa appears identical to its appearance shortly before the earthquake. Two areas of fractures —believed formed by the May 12 2015 aftershock— were observed on the engineered part of the end moraine from a helicopter during an inspection undertaken by the U.S. Geological Survey at Tsho Rolpa. Photos from 27 May by Brian Collins/USGS, courtesy of USAID-OFDA (Office of Foreign Disaster Aid). Distributed via
NASA Goddard on Flickr.

For many, including Dan, it rose from a need to contribute to the humanitarian effort. Despite having trained as a geomorphologist and actively researching Alpine natural hazards, prior to the Gorkha earthquake he’d not had the opportunity to apply his knowledge and expertise to help others. It allowed him to offer help in the same way a medic might do by flying out to the scene of a disaster and offering medical expertise and treating the injured.

For Dalia, the positive impact made in the Nepal crisis by the international effort of quickly gathering, sharing and interpreting Earth observation data, was an important driver in keeping her linked to the project.

This effort is now seeing a life beyond the Nepal earthquakes. NASA satellites had previously been involved in the acquisition of data sets to aid in humanitarian crisis, such as in the aftermath of hurricanes. The successful approach taken during the Nepal earthquakes will now help coalesce NASA’s disaster programme and how NASA will respond to natural hazards in the future. It is leading to a more formalised disaster response programme.

The lessons learnt from the Nepal earthquake are ongoing, with much still being done in the scientific realms to better understand the hazards posed by the tectonics of the region, and associated geohazards triggered by the earthquakes. Many of the international collaborations fostered during the crisis are ongoing and will hopefully mean an improved response to future natural hazards in the region.

By Laura Roberts Artal, EGU Communications Officer. With many thanks to Dalia Kirschbaum and Dan Shugar.

References

Schwanghart, W., Bernhart, A., Stolle, A., et. al.,: Repeated catastrophic valley infill following medieval earthquakes in the Nepal Himalaya, Science, vol. 351, 6269, 147-150, doi: 10.1126/science.aac9865, 2016.

Kargel, J. S., Leonard, G. J., Shugar, D.H., et al.,: Geomorphic and geologic controls of geohazards induced by Nepal’s 2015 Gorkha earthquake, Science,vol. 351, 6269, 147-150, doi: 10.1126/science.aac8353, 2016.

Unfortunately, some of the publications referenced in this post are close access – but other links included in this post, as well as the post itself, hopefully convey the overall message of the research.

Imaggeo on Mondays: The retreating glaciers of the Svaneti Range, Georgia

Imaggeo on Mondays: The retreating glaciers of the Svaneti Range, Georgia

Today’s Imaggeo on Mondays picture shows the central section of the Svaneti Range, located in the Svaneti Region – a historic province of northwestern Georgia. The range is the second biggest range formed by the modern glaciation on the southern slopes of the Georgian Caucasus Mountains. In today’s post, Levan Tielidze, a researcher at Ivane Javakhishvili Tbilisi State University, writes about the ice capped peaks of these high mountains and highlights the precarious balance of this cryospheric system.

Svaneti range is approximately 100 km long and is distinguished by the height of its relief, as well as by the fact that the area covered by glaciers in the region exceeds that covered elsewhere in the southern slopes of the Georgian Caucasus.These features define the range and lead it to be divided into three sections: eastern, central (shown in this picture) and western. The eastern and western sections are lower in altitude than the central region and modern ice cover cannot be found there, with the exception of Mount Dadiashi which stands at 3535 m asl.

However, glaciers do cap the peaks in the central areas of the range, and can be found between the sections of Lasili and Leshnuri. Here is where you’ll find the highest peak of the mountain range: Laila (Laila-Lehli) -4009 m asl.

The glaciers in this region are retreating and losing volume. Data from the 1960s indicated that glaciers in the range numbered up to 48 and covered an area of approximately 27.76 km2 , equivalent to the size of just over 2500 football pitches. By 2014 the area covered by the glaciers in the region had shrunk by 27.5% and now only covers approximately 20.13 km2.

Some of the largest glaciers of the northern slopes of the range are formed on Laila peak, which itself is covered by a glacier cap. Among these glaciers the largest is Eastern Laila, located in the Khumpreri River basin. The glacier is formed of two ice streams which flow from separate valleys. In 1960 the glacier area was  close to 5.96 km2; its terminus ended at a height of 2300 meters asl. By 2014 the eastern Laila’s area decreased to 3.55 km2 and has retreated to an altitude of 2640 m asl. The total glacier length is now approximately 4.52 kilometers.

The glaciers are an important source of water for agricultural production in Georgia, and runoff in large glacially-fed rivers (Kodori, Enguri, Rioni, Tskhenistskali, Nenskra) supplies several hydroelectric power stations. In addition, glacier outburst floods and related debris flows are a significant hazard in Georgia and in the Caucasus. Future trends in glacier change are thus a topic of considerable interest to the region.

By Levan Tielidze, Institute of Geography, Tbilisi State University, Georgia

If you pre-register for the 2016 General Assembly (Vienna, 17 – 22 April), you can take part in our annual photo competition! From 1 February up until 1 March, every participant pre-registered for the General Assembly can submit up three original photos and one moving image related to the Earth, planetary, and space sciences in competition for free registration to next year’s General Assembly!  These can include fantastic field photos, a stunning shot of your favourite thin section, what you’ve captured out on holiday or under the electron microscope – if it’s geoscientific, it fits the bill. Find out more about how to take part at http://imaggeo.egu.eu/photo-contest/information/.

Looking back at the EGU Blogs in 2015: welcoming new additions

Looking back at the EGU Blogs in 2015: welcoming new additions

It’s a little over 12 months since we launched the new look EGU blogs and with the holidays and new year approaching, what better time to take stock of 2015 as featured in the EGU Blogs? The past year has been full of exciting, insightful and informative blog posts. At the same time, we’ve welcomed new additions to the network and division blogs.

The network blogs

A recent highlight of the year has to be the addition of a new blog to the network: please welcome our new blogger Professor David Pyle, author of VolcanicDegassing – a blog about volcanoes and volcanic activity. In 2016 you can look forward to posts about David’s ongoing research in Latin America, the Caribbean, Ethiopia and Europe, as well as historical and contemporary descriptions or other representations of volcanic activity across the globe.

Vesuvius in eruption, April 26, 1872. Original caption ‘from a photograph taken in the neighbourhood of Naples”. (Palmieri and Mallet, 1873). Published in the Decemeber 15th post:  'The first volcanic eruption to be photographed?'

Vesuvius in eruption, April 26, 1872. Original caption ‘from a photograph taken in the neighbourhood of Naples”. (Palmieri and Mallet, 1873). Published in the Decemeber 15th post: ‘The first volcanic eruption to be photographed?

Richly illustrated and referenced posts have featured across the network throughout the year, with topics ranging from the journey aerosol particles go on throughout their life time, through to the role peculiarities of geology and geomorphology play in deciding on big international governance.

The most popular post written in 2015 was brought to you by Jon Tennant and featured the ichthyosaurs, an unusual turtle-fish-dolphin like marine reptile which cruised the seas 250 million years ago. The post focuses on the discovery of an ichthyosaur fossil named David, or rather Cartorhynchus lenticarpu as it is formally known, and how the remarkable specimen sheds light on the origins of these unusual creatures.

Matt Herod’s post on Geosphere in early December 2014 featuring the story behind the legal battle of Italian geochemists who were sued after publishing results stating that they could not find above background levels of depleted uranium in former Italian military firing ranges, is the second most read post across the network in the past year. With a strong resemblance to the L’Aquila verdict against the Italian seismologists, which was resolved in 2014, Matt highlights there are lessons to be learnt from both cases in the post.

Natural hazards and the April 2015 Nepal earthquakes featured heavily across the network too. In the immediate aftermath of the earthquake, the Geology for Global Development blog compiled a comprehensive list of links and resources which readers could consult to find out up to date and reliable information about the events in Nepal. A list which is still a useful resource some 8 months after the tragedy and which is the third most popular post on the network this year. Simon Redfern, of Atom’s Eye View of the Planet, wrote a piece on how and why scientists have identified Kathmandu valley as one of the most dangerous places in the world, in terms of earthquake risk.

With many of the network bloggers being in the thick of PhD research or having recently submitted their thesis, tips and hints for a successful PhD completion also proved a focus of the content across the network. Despite being originally written in April 2013, Jon Tennant’s blog post on why and how masters students should publish their research was the most popular post of the year! The most read post from Geology Jenga advertised a new, and free, online course on how to survive the PhD journey.

The division blogs

Since their launch last December, the division blogs have gone from strength to strength. Keeping you updated with news and information relevant to each division, they have also featured accounts of field and laboratory work, as well as professional development opportunities and open vacancies.

Throughout the year the division blogs have been enhanced through the addition of the Atmospheric Sciences, Energy Resources and Environment blogs and, most recently, the Biogeosciences Division blog too.

Cross-section of the age of the Greenland Ice Sheet from radar data. Credit: NASA's Scientific Visualization Studio and MacGregor et al., 2015.

Cross-section of the age of the Greenland Ice Sheet from radar data. Credit: NASA’s Scientific Visualization Studio and MacGregor et al., 2015.

The most popular post of the year was shared by the Seismology Division and touched upon the controversial topic of whether cloud formations can be used to predict earthquakes, while the Cryosphere Division blog’s image of the week of late October featuring a cross section of the Greenland Ice Sheet was the second most popular post. Round-up posts about the 2015 General Assembly, tips for convening sessions at the conference, as shared by Geodesy Division, and some soul searching by the Geomorphology Division as to why a proposed session wasn’t included in the final conference programme also proved very popular.

Get involved

Are you a budding science writer, or want to try your hand at science communication? All the EGU Blogs, from GeoLog (the official EGU blog), through to the network and division blogs, welcome guest contributions from scientists, students and professionals in the Earth, planetary and space sciences.

It couldn’t be easier to get involved. Decide what you’d like to write about, find the blog that is the best fit for your post and contact the blog editor – you can find all editor details on the individual blog pages. If in doubt, you can submit your idea for a post via the Submit a Post page on GeoLog, or email the EGU Communications Officer, Laura Roberts, who can help with initial enquiries and introduce you to individual blog editors.

Don’t forget to a look at the blog pages for a flavour of the content you can expect from the new, and existing, blogs in 2016. The blogs are also a great place to learn about new opportunities, exciting fields of research and keep up to date with news relating to the upcoming 2016 General Assembly.

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