The 2015 Gorkha-Nepal Earthquake: Hazard and Risk Information Innovations
Since the 25 April 2015 Gorkha-Nepal Earthquake (M 7.8), Nepal has experienced more than 400 aftershocks, including the M 7.3 12 May 2015 aftershock. The April 2015 Gorkha-Nepal Earthquake is commonly known as the Gorkha earthquake sequence. The cumulative impact of the April and May 2015 Gorkha earthquake sequence has killed over 9,000 people and injured more than 23,000. Estimated economic losses are 10 billion. An estimated 500,000 buildings have been damaged or destroyed (S-UK. 2015, Karnak 2015, USGS 2015a, NSC 2015).
During the international response to the April 2015 Gorkha-Nepal Earthquake, we began to investigate how hazard and risk specialists collect, manage, analyze and communicate data. The goal was to document who was developing information during an international research response initiative to support Nepalese communities in times of rapid socio-economic change, and what have been the outcomes.
Aerial footage taken from a drone shows damaged caused by the April 27, 2015 earthquake in Nepal.
A Review of the 2015 April and May 2015 Gorkha –Nepal Earthquake Sequence
Four major geophysical processes create geohazard risk for communities in the Kathmandu area/Gorkha Fault Zone. These are: i) an active earthquake belt between Tibetan and Indian plates, ii) many active crisscrossing fault lines in the southern and western areas, iii) Kathmandu city is located ancient lakebed, prone to liquidation and iv) high probability of another large scale earthquake event (Dixit. 2000). As documented elsewhere, it was widely known that because of the regional geology, land use patterns, architecture, and the 2008 Hazard Risk Profile of Nepal’s 75 districts, an intense earthquake would have a large impact on Nepalese communities (van Zijll de Jong 2015, van Zijll de Jong et al. 2015).
Changes to Earthquake Research Response Teams
The April and May 2015 earthquakes reveal the physical impact earthquakes can have on an impoverished country (World Bank 2015). The April 2015 earthquake triggered a huge avalanche in the Langtang valley, and an avalanche on Mount Everest that killed 19 and injured over 60 people. Aftershocks have triggered fresh avalanches in Northern India and Mount Everest (Adnan 2015). Avalanches and landslides caused damage to houses and commercial properties. The May 2015 earthquake also confirmed that valley-blocking landslides pose considerable hazard to many villages in Nepal because they affect roads and threaten supply chains of food, medical supplies and humanitarian assistance (USGS 2015 b).
The aftershocks spawned the evolution of new scientific interest in how to investigate the impact of earthquake-associated hazards (such as landslides and avalanches) on communities (EERI 2015). Scientific research efforts are verified in the following initiatives:
International group of remote-sensing scientists to document the extent and spatial distribution of land sliding (USGS 2015b)
Comparative analysis of the before-and-after April 2015 Gorkha-Nepal Earthquake radar images from Europe's Sentinel-1A radar satellite to determine if the ground near Kathmandu lifted one meter, and Mount Everest decreased in height (Oskin 2015).
Earthquake Engineering Research Institute multidisciplinary reconnaissance team to Nepal from May 31–June 7, 2015 to investigate nine main themes (EERI 2015)
Recognizing a Variety of Hazard Risks associated with Earthquakes
Scientific research reports demonstrate that Gorkha earthquake sequence continues to threaten Nepalese communities with following earthquake-associated hazards:
continued aftershocks and ground shaking
Lessons that can be Drawn from the Gorkha-Nepal Earthquake Sequence for Canada
Despite the many potential benefits of rapidly deploying geoscience research teams, providing situational awareness, and performing geohazard risk analysis, much work remains to be done in integrating post event geohazard risk information into response activities. One point of progress is that new response “crisis mapping” teams were deployed to use new technological applications to collate post disaster primary and secondary sources of information. This geoinformation was mapped to communicate real time hazards, risk and vulnerability. As this is an ongoing project, lessons to be learnt for the Canada context will be discussed at another time (van Zijll de Jong et al. 2015)
Another point of progress is that geohazard research teams helped to identify the causes and the likelihood of 2015 Gorkha earthquake sequence geohazard risks. However, as noted by Sir Mark Walport (2015), geoscience information collectors (USGS and others) did not effectively communicate the Gorhka zone geohazard risk information they had collected to decision makers and the public during the emergency and recovery phase (Walport 2015). This information was critical for refining the post event communicating strategy that was taking into account the public’s fear of geohazard risk, concerns related to the potential consequences from large aftershocks and landslides during the monsoon season, as well as the likelihood of these events occurring. If the geoscience information had been transmitted, it would have helped to speed up the implementation of geohazard risk communication strategy during the state of emergency phase.
Anticipating an Event: Preparing a Geohazard Risk Communication Strategy
Importantly, Nepal has underscored the importance of preparing a geohazard risk communication strategy for response and recovery agencies, government agencies, the media, insurance companies, volunteers and Nepalese communities.
What happened in Nepal can provide lessons for Canada to deal with earthquake risk. As Mertl (2015) indicates, there are significant lessons Canada can learn when it comes to being prepared for an earthquake event. Recently, our research team presented at the 2015 Canadian Risk and Hazards Network Symposium (http://www.crhnet.ca/symposium). We argued that good geospatial information for disaster risk management provides the sort of geohazard risk information required for a credible communication strategy. Canada needs to prepare by investing in a post event information initiative designed to reduce the public’s fears and concerns. To this end, available information on the causes, consequences and potential likelihood of continued aftershocks and ground shaking, landslides, avalanches, liquefaction, lateral spread and fault rupture must be readily available to wide group of stakeholders and decisions makers, should an event occur.
Shona is involved in risk based land use planning in Canada (Geological Survey of Canada, Laurentian University, Canada); and natural hazard disaster risk management projects (New Zealand, Samoa, and Australia). She has two decades experience in global environmental change and sustainable development projects Southern Africa).
Please the list of references in this post here.
Views expressed in blog posts reflect those of the author, and not necessarily those of the CFES.