Impact of Empirical Green’s Functions on Estimating Rupture Velocity with Back-Projection Across Various Rupture Scenarios

Miguel Álvarez-Martinez, Liuwei Xu, & Lingsen Meng

Published September 8, 2024, SCEC Contribution #13749, 2024 SCEC Annual Meeting Poster #026

Understanding rupture propagation on faults and accurately measuring source parameters are crucial for enhancing earthquake response times, potentially saving lives, and minimizing damage. We developed a method to utilize waveform data from aftershocks of the 2011 Mw 9.1 Tohoku Earthquake and form Empirical Green’s Functions (EGFs) to simulate a variety of rupture scenarios. Our analysis tested various parameters to assess their impact on rupture velocity estimation using back-projection (BP) techniques (e.g. Kiser and Ishii, 2017) on rupture scenarios with realistic slip distribution and variable rupture speeds. We examined data from two different seismic arrays (U.S. vs. European stations) and used the 6 aftershocks to form EGFs for each seismic array, applying three slip models (Uniform, Landers, and Izimit), and four rupture velocities (2 - 5 km/s). Results indicated significant artifacts in the BP leading to an underestimation of rupture velocity due to coda waves masking P-waves. The accuracy of velocity estimations was dependent on the receiver array and rupture scenario while moderate effects are also seen due to the choice of EGFs and slip models. This study fills a gap by providing controlled experiments on rupture propagation speed estimations based on EGF estimations, supporting the development of back-projection imaging for fault rupture analysis. Future work will employ the Incoherent Green’s Function (IGFs) to mimic the earthquake data seen by EGFs allowing us to simulate earthquakes while bypassing limitations due to lack of EGF events.

Key Words
earthquake source imaging; back-projection; tohoku earthquake

Citation
Álvarez-Martinez, M., Xu, L., & Meng, L. (2024, 09). Impact of Empirical Green’s Functions on Estimating Rupture Velocity with Back-Projection Across Various Rupture Scenarios. Poster Presentation at 2024 SCEC Annual Meeting.

Related Projects & Working Groups
Seismology