Student: Bryan Stressler, Graduate Student in Earth and Environmental Sciences, University of Iowa
Faculty Advisor: William Barnhart
Characterizing Static Stress Changes in Subduction Zone Environments: Limitations from Onshore Geodetic Observations
Coulomb stress change is a metric that is frequently used to investigate potential earthquake-triggering relationships in a variety of tectonic environments. In subduction zones, regions that produce the world’s largest earthquakes, geodetic observations of earthquake deformation are typically limited to onshore regions while fault slip dominantly occurs offshore. This limited spatial coverage impacts the resolution of fault slip models, which propagates into calculations of Coulomb stress change. We are implementing a series of synthetic tests to investigate the reliability of these calculations in subduction zones and will apply the results to investigate triggering of aftershocks of the 2010 Mw8.8 Maule, Chile earthquake. We seek to test off-fault aftershocks (those that do not occur on the mainshock fault plane) as a proxy for larger triggered earthquakes, for which the sample size is too small for robust statistical tests.