University of Otago Geology Seminar

As part of the MBIE-funded RNC-2 project, hundreds of thousands of years of synthetic catalogs were generated for New Zealand fault systems using a physics-based earthquake simulator (RSQSim). In my thesis, I evaluated synthetic earthquakes from RSQSim to assess their implications for probabilistic seismic hazard analysis (PSHA). I compared seismicity, seismic moment rate, and PSH estimates from RSQSim with the New Zealand National Seismic Hazard (NZ-NSHM) 2010 and 2022. My findings show that RSQSim can generate earthquake rates and PSH estimates that are similar to the NZ NSHMs for the South Island, where crustal faults primarily accommodate plate deformations. However, I found there to be significant discrepancies in the North Island, where the Hikurangi subduction interface and crustal faults jointly accommodate the overall deformation. On the Main Himalayan Thrust (MHT), I used geologic, seismic, and geodetic datasets to model the 3D geometry, slip rates, and friction into RSQSim to simulate 10,000-kyr seismicity. I observed that seismicity rates, spatial distribution of events, and rupture extent from MHT RSQSim are compatible with historical and instrumental earthquake records along the MHT. Furthermore, PSH estimates produced using synthetic earthquakes from RSQSim showed good agreement with classical PSHA. Overall, my findings indicate that RSQSim can replicate observed seismicity and the seismic hazard estimates on the South Island of New Zealand and the MHT, but further improvement in the RSQSim model is required for the North Island.

This talk will be available via Zoom, but not recorded https://bit.ly/otagogeology