Date of Award
Doctor of Philosophy
AARON A. VELASCO
Seismic waves can trigger earthquakes and tremor at large distances from the causable event. Dynamic triggering occurs when the surface waves from large earthquakes change the stresses conditions on previously overstressed faults, promoting failure. To understand the causative stresses and environments behind dynamic triggering, we model the change in the stress field that the passing of Rayleigh and Love waves cause on a fault plane of arbitrary orientation relative to the direction of propagation of the waves, and apply a Coulomb failure criterion to calculate the potential of these stress changes to trigger seismicity. We apply our model to three different study regions and compare with observations. In the first case, we compare our model results with data from dynamically triggered earthquakes in the Australian Bowen Basin, Our data analysis shows that for this region, surface waves arriving at 45 degrees from the average local stress field are the most likely to trigger local seismicity. This agrees with our observations. In the second study case, we show how the same model can be applied to dynamic triggering of Non-volcanic tremor (NVT). Our modeling predicts the potential of a seismic wave to trigger slip on a fault plane promoting NVT. We search for tremor in the Central Range in Taiwan triggered by surfaces waves and compare the observations with our modeling. In the last study case, we present our modeling of the dynamic stress that triggered two events in Utah, one triggered by the 1992 Landers earthquake and the other by the 2002 Denali Fault earthquake. We show how dynamic stress modeling can be used to discriminate between the two axial planes of a first motion focal mechanism of a dynamically triggered event.
Received from ProQuest
Gonzalez-Huizar, Hector, "Insight Into The Physics Of Rupture: Dynamic Triggering Seismicity" (2009). Open Access Theses & Dissertations. 268.