Exciting news! We're transitioning to the Statewide California Earthquake Center. Our new website is under construction, but we'll continue using this website for SCEC business in the meantime. We're also archiving the Southern Center site to preserve its rich history. A new and improved platform is coming soon!

Isotropic source components of events in the 2019 Ridgecrest earthquake sequence

Xin Wang, Yifang Cheng, Zhongwen Zhan, & Yehuda Ben-Zion

Published August 11, 2020, SCEC Contribution #10374, 2020 SCEC Annual Meeting Poster #068

We investigate source mechanisms of 256 M3.5+ aftershocks of the 2019 M7.1 Ridgecrest earthquake, which ruptured a complex fault system in the Eastern California Shear Zone. The full moment tensors are derived with a generalized “Cut and Paste” inversion using a 3D velocity model and regional (<=100 km) three-component broadband waveform data. We perform multiple inversions of moment tensors using waveforms recorded by stations within different epicentral distance ranges, with uncertainties of source parameters estimated by a bootstrapping method. The results show that about 60 aftershocks have significant isotropic components that are about 5%-15% of the total moments of the events. In contrast, most events do not have statistically significant Compensated-Linear-Vector-Dipoles components. Earthquakes with large isotropic components are mainly distributed around rupture ends, intersection, and the areas of high mainshock coseismic slip, suggesting damage-related isotropic radiations. The values of isotropic components increase by adding more waveforms from near-event stations into the inversions, highlighting the importance of nearfield data in understanding realistic source behaviors.

Key Words
2019 Ridgecrest; Moment Tensor; Isotropic components

Wang, X., Cheng, Y., Zhan, Z., & Ben-Zion, Y. (2020, 08). Isotropic source components of events in the 2019 Ridgecrest earthquake sequence. Poster Presentation at 2020 SCEC Annual Meeting.

Related Projects & Working Groups