The New USGS Near-Real-Time Ground Failure Product and Its Performance for Recent Earthquakes

Date: 4/24/2019

Time: 06:00 PM

Room: Grand Ballroom

As of September 2018, a new USGS earthquake product called “Ground Failure” provides quantitative estimates of the severity and extent of earthquake-triggered landslide and liquefaction hazards in near-real-time to the public through the USGS webpages. The product provides a generalized summary of hazard and population exposure, communicated through alert levels and summary statistics, as well as interactive maps of the estimated spatial distribution. The product is intended to provide situational awareness of areas with higher probability of experiencing ground failure to officials, responders, and the public in the time window between the event and reconnaissance. Ground failure results were publicly available for three significant earthquakes in late 2018: Hokkaido, Japan (M6.6), Palu, Indonesia (M7.5), and Anchorage, Alaska (M7.0). Each of these earthquakes tested the product in different ways, revealing both strengths and weaknesses of the underlying models, product design, and communication effectiveness. Overall, we found that the alert levels, which span four logarithmic levels from green to red, were effective at communicating the general importance of ground failure for these events. However, their definitions are qualitative and are thus hard to test quantitatively. Both the Palu and Anchorage earthquakes triggered lateral spreads, flow-slides, cracking, and subsidence that were societally impactful but were not well-represented by either model. In addition, the liquefaction model tends to overestimate hazard for areas of weaker shaking while the resolution of the landslide model slope data (~250 m) is too coarse to effectively capture important smaller steep slopes such as coastal bluffs or road cuts. Beyond evaluating model performance, we also discuss how the product has been received by the scientific community, officials, the media, and the public. The feedback and lessons learned from the response to recent earthquakes will guide the path forward as we continue to improve and expand the USGS Ground Failure product.

Presenting Author: Kate E. Allstadt

Authors