Improved understanding of extent and size of tsunamigenic earthquakes through geodetic and tsunami datasets
Williamson, Amy L.
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This dissertation seeks to constrain the rupture size and magnitude of tsunamigenic earthquakes through the inclusion of data from both traditional geodetic instruments and recently deployed open-ocean tsunami gauges. First, I assess the sensitivity of the subduction zone model space to geodetic and tsunami waveform data. This provides a picture of where we can and cannot resolve rupture models when data is limited. It also highlights the issues that can ensue if poorly constrained models are used to study earthquakes. Second, I conduct an event-based joint inversion incorporating both geodetic and tsunami data for the 2015 Illapel, Chile earthquake. This includes merging codes for tsunami propagation, fault deformation, and linear inversions. The result of the joint inversion is a model space that is not only resolved near the coastline where geodetic data exists, but also near the trench where tsunami data is significantly more sensitive. The third component of this dissertation is an analysis of the feasibility of open-ocean data for rapid source inversions. This builds on current tsunami warning center methodologies but with a focus on the time constricted scenarios of a near-field warning from a local tsunami source. Here I analyze four different regions for their tsunamigenic potential as well as their potential to have instrumentation that will provide enough lead time during a local event to record data that is meaningful for disaster management and hazard warnings. The combination of these different aspects of tsunami-geodetic joint inversions illustrates both the improved model resolution and understanding of what was once a poorly constrained problem.