Collaborative Research: Parameterizing The Drivers and Timing of Post-Earthquake Landslides

University Of Washington, Seattle WA

Investigators

Abstract

This research project explores the drivers of landslides that occur after earthquakes, which currently are not well understood. Following destabilization of the terrain from earthquakes, landslides tend to occur more frequently, presenting a persistent hazard that impacts socioeconomic well-being and community recovery. While this increased landslide occurrence after earthquakes has been documented, the reasons why this phenomenon arises are poorly constrained. In the absence of physics-based insight towards this problem, we are ill-equipped to prepare and mitigate landslide hazards following seismic events, leaving our communities vulnerable at a critical time for recovery. In collaboration with partners in New Zealand, which experienced significant post-seismic landsliding in recent years, this project will create a physics-based framework to evaluate drivers and the timing of post-seismic landslides at local and regional scales. This work will be accomplished through constraining the physical mechanisms and evolving material changes that drive landslides to occur more frequently following earthquakes. Through these activities, engineers, planners, and scientists will be better equipped to design and prevent the impacts of post-earthquake landslides, enabling the more resilient design of infrastructure systems and better planning for recovery after seismic events. This project will also allow sharing lessons of direct relevance learned from recovery in New Zealand with the transportation and community planners in the US Pacific Northwest, which is overdue for a strong, subduction zone earthquake. The primary goal of this research project is to parametrize the spatiotemporal drivers of post-earthquake landslides. Evaluation of the magnitude and timing of elevated post-earthquake landslide activity is primarily limited to empirical observation from remotely-sensed data. This evolving landslide activity has been ascribed to various phenomena; however, there are no physics-based approaches to test hypotheses regarding the drivers of post-seismic landsliding, evaluate their respective influences, or provide predictive power towards assessing post-earthquake landslide hazard. This research project will establish a comprehensive physics-based platform for understanding why strong earthquakes increase subsequent landslide activity. Through these activities, we seek to (1) establish a framework for evaluating earthquake-induced hillslope damage, (2) isolate how climate, geology, seismicity, vegetation, and topography influence observed post-earthquake landslide activity, and (3) test hypothesized influences on the timescales of post-earthquake landslide activity. These activities will be performed in continued, close collaboration with GNS Science in New Zealand, who currently are leading an extensive research effort to understand and predict post-earthquake landsliding after the 2016 Kaikoura event. We will expand and complement GNS Science data collection and statistical modeling efforts by adding a geomechanics perspective and enable a formal, international exchange of knowledge. We will test a research-to-practice engagement program developed by the GNS Science social science team throughout the scientific process with the Oregon Department of Transportation, who is interested in planning for post-earthquake recovery. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.