Using Earthquake Scenarios to Communicate Himalayan Earthquake Risk and Facilitate Mitigation Planning
Abstract
Earthquakes along the Himalayan plate boundary fault system have killed 95,000 people since 2000 alone. Sections that have not ruptured in centuries may generate M8 earthquakes or larger, causing humanitarian catastrophe. Even smaller events kill thousands and destroy vulnerable buildings.
In westernmost Nepal, a very large earthquake has not occurred since 1505 AD. Communities in this primarily rural region are often unaware of their major earthquake risk and are not prepared; disaster management efforts focus on yearly landslides and floods. To explain earthquake risks and how to reduce them, GeoHazards International developed earthquake scenarios with short-story style narratives, then led action planning with local professionals and officials in three districts: Bajhang, Dadeldhura, and Rukum (West). Our goal is to motivate and support readiness actions before the next deadly earthquake. Our hypothetical M7.8 earthquake scenarios show damage and consequences based on our fieldwork, interviews, and loss estimates. USGS ShakeMap estimates yield PGA up to 0.8g and PGV up to 50 cm/s. Approximately 50-67% of buildings (mostly rubble stone masonry and non-ductile concrete) would collapse, depending on the district. The mid-day, dry season event would cause approximately 4,100, 3,200, and 4,000 fatalities in the respective districts. An estimated 7,000-10,000 serious injuries per district would overwhelm hospitals. Some 700-6,000 landslides would occur (this would double during the monsoon), blocking the sparse roads and isolating people from medical care, aid and supplies, markets for goods, and schools. Trail bridges may take a year to repair, isolating people not on the road system. Repairs to damaged communication, water, and power systems would be slow due to interdependencies. The disaster scenario and recommendations emphasize how managing building and road development, and safeguarding schools, hospitals, and critical utilities can reduce or mitigate consequences. This will require a change in practices, and in some cases substantial investments over time. The action plans we developed with local stakeholders define changes that will improve disaster resilience, assign responsibility for action to specific stakeholders or agencies, and lay out short, medium and long-term priorities.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.T43A..04R
- Keywords:
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- 1242 Seismic cycle related deformations;
- GEODESY AND GRAVITY;
- 7230 Seismicity and tectonics;
- SEISMOLOGY;
- 8004 Dynamics and mechanics of faulting;
- STRUCTURAL GEOLOGY;
- 8123 Dynamics: seismotectonics;
- TECTONOPHYSICS