EARTHQUAKE-TRIGGERED LANDSLIDES AND LIQUEFACTION: HOW BAD WILL IT BE?

Some major earthquakes bring down thousands of landslides and liquefy wet, soft ground causing widespread damaging settlements and lateral spreads all in a matter of minutes and over a vast region. Where this ground failure intersects with human populations and their infrastructure, it can cause fatalities, costly damage, and widespread disruption to transportation and lifelines all in nearly an instant. Fortunately, such severe ground failure-causing earthquakes are fairly rare. Many major earthquakes result in very little ground failure or few human impacts, others fall somewhere in between. Despite a long history of established research on the topic, the reasons for this variability in the severity and style of response of the terrain to shaking from a given earthquake still can sometimes evade us. It can also take several days or longer to understand the extent of what actually occurred, a time window in which decisions about the response and recovery still need to be made.

This need to differentiate potentially severe ground failure-triggering earthquakes rapidly has prompted research and development of regional and global geospatial models that can be applied in near-real-time. A key ingredient for the development of these models is high quality inventories, ideally that combine remote sensing and field reconnaissance to constrain the spatial extent of ground failure. The inventories need to be developed for major ground failure events as well as mild ones. In this talk, I will review the state-of-the-art of regional and global scale modeling as well as community efforts to collect more and higher quality post-earthquake datasets. I will also detail how the near-real-time USGS ground failure product, which was deployed nearly 4 years ago, has been performing for recent global earthquakes and the lessons we have learned. Based on that experience, I will discuss the research and development that is still needed to better constrain and communicate likely ground failure hazard and population exposure for future earthquakes.