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Rupture process of the 2019 M 6.4 and M 7.1 Ridgecrest earthquakes imaged with local and teleseismic back-projections

Yuqing Xie, Lingsen Meng, & Han Bao

Published August 14, 2020, SCEC Contribution #10641, 2020 SCEC Annual Meeting Poster #072

We used the multi-array local back-projections (MLBP) and slowness-enhanced back-projection (SEBP) to image the coseismic rupture process of the 2019 M 6.4 and M 7.1 Ridgecrest, California earthquake sequence, which occurs on multiple complex fault structures. For MLBP, we develop a method to construct station clusters based on waveform coherency for stations within 2.5° from the epicenters. Our results show that the M 6.4 quake initiated on a 8-km-long NW-trending segment, before rupturing the primary SW-trending fault at the speed of ~1.3 km/s. The M 7.1 quake extends bilaterally for 10 km and 25 km, on the NW and SE portion of the fault, respectively, at the speed of 1 - 1.5 km/s, consistent with the SEBP result. The rupture path agrees with the surface rupture trace inferred by aftershocks. The slow rupture speed is related to the low structural maturity of the fault. The MLBP is able to accurately constrain the rupture process with local seismic arrays, which means less time to collect data and has great potential to be used for rapid earthquake hazard estimation. The optimized clusters and parameters such as cluster size, epicentral distance can be used for rapid hazard mitigation for future earthquakes in Southern California.

Key Words
Ridgecrest Earthquakes, Back-projection, Southern California Network

Xie, Y., Meng, L., & Bao, H. (2020, 08). Rupture process of the 2019 M 6.4 and M 7.1 Ridgecrest earthquakes imaged with local and teleseismic back-projections. Poster Presentation at 2020 SCEC Annual Meeting.

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