Group B, Poster #058, Seismology

Moment Tensor Catalog for California Using 3D Green's Functions

Claire D. Doody, Arthur J. Rodgers, Andrea Chiang, Michael Afanasiev, Christian Boehm, Lion Krischer, & Nathan Simmons
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Poster Presentation

2022 SCEC Annual Meeting, Poster #058, SCEC Contribution #12502 VIEW PDF
Accurate moment tensors are vital for our understanding of earthquake processes and stress regimes in tectonically active regions. Most moment tensor computations are done using one-dimensional velocity models to compute Green’s Functions, as 1D Green’s Functions are less computationally expensive to compute. Despite the added computational cost, studies have shown that computing moment tensors using three-dimensional Green’s Functions from a 3D velocity model provides results with higher variance reductions (e.g. Kim et al., 2011; Chiang et al., 2022). We therefore present moment tensor solutions for over 100 events across California and Nevada from the past 20 years that are calculated 3D Green’s Functions. The 3D Green’s Functions are calculated from CANVAS, an adjoint waveform tomography model of California and Nevada (Doody et al., in prep), in the period band of 20-50 seconds. We show that our moment tensor catalogue fits the observed data better than solutions from the Global Centroid Moment Tensor catalog (GCMT) and local catalogues across the region, with higher variance reductions (VR) and smaller time shifts. Most importantly, the moment tensors calculated using CANVAS show good fits (VR> 70%) to the observed data at stations up to 800 km away. Our ability to accurately simulate data at distant stations has implications for moment tensor analysis in regions such as Walker Lane and off-shore Mendocino, where close-in stations are unavailable.

Abstract for the 2022 Southern California Earthquake Center Annual Meeting, to be held in Palm Springs, CA, September 11-14, 2022. This work was supported by LLNL Laboratory Directed Research and Development project 20-ERD-008. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. LLNL-ABS- 838882