Co-Seismic Inversion and Post-Seismic Deformation Mechanism Analysis of 2019 California Earthquake

Chengsheng Yang,Chaoying Zhao,Sainan Zhu,Ting Wang,Jihong Dong,Bingquan Han

doi:10.3390/rs13040608

Chengsheng Yang, Chaoying Zhao + Show 4 more

Open Access

https://doi.org/10.3390/rs13040608

Copy DOI

Abstract

In July 2019, a series of seismic events, including a magnitude (Mw) 7.1 mainshock and Mw 6.4 foreshock, occurred in Eastern California. Studying these seismic events can significantly improve our understanding of the Eastern California tectonic environment. Sentinel-1A and ALOS-2 PALSAR images were utilized to obtain co-seismic deformation fields, including mainshock and foreshock deformation. The Okada elastic dislocation model and ascending and descending orbit results were used to invert the co-seismic slip distribution and obtain a co-seismic focal mechanism solution. Using ascending Sentinel-1A images, a time-series deformation was obtained for 402 d after the earthquake, and the deformation evolution mechanism was analyzed. The maximum uplift caused by the co-seismic mechanism reached 1.5 m in the line of sight (LOS), and the maximum subsidence reached 1 m in the LOS. For 402 d after the earthquake, the area remained active, and its deformation was dominated by after-slip. The co-seismic inversion results illustrated that California earthquakes were mainly strike-slip. The co-seismic inversion magnitude was approximately Mw 7.08. The Coulomb stress change illustrated that the seismic moment caused by the co-seismic slip was 4.24 × 1026 N × m, which is approximately Mw 7.06. This finding is consistent with the co-seismic slip distribution inversion results.

Highlights

On 4 July 2019, and 6 July 2019, a series of earthquakes occurred successively in California, United States, including a magnitude (Mw) 6.4, Mw 7.1, and many aftershocks
Li et al (2019) obtained the co-seismic deformation field using Sentinel-1A, Advanced Land Observing Satellite-2 (ALOS-2), and Global Positioning System (GPS) data, inverted the source parameters of the mainshock and foreshock, and calculated the Coulomb stress changes caused by the two earthquakes [1]
It can be seen from the co-seismic deformation field (Figure 3) that the ascending and descending interferograms covered the earthquake epicenter

Summary

Introduction

On 4 July 2019, and 6 July 2019, a series of earthquakes occurred successively in California, United States, including a magnitude (Mw) 6.4 (foreshock), Mw 7.1 (mainshock), and many aftershocks. Chen et al obtained a foreshock and mainshock asperity model using Sentinel-2 images, GPS, and seismic waveform datasets [2]. Barnhart et al acquired co-seismic deformation fields from the ascending and descending of Sentinel-1A, and they calculated the optimal slip model and Coulomb stress for both the mainshock and foreshock [3]. Liu et al selected strong-motion recordings from GPS stations near the epicenter. They conducted a series of preliminary finite fault inversions to explore the

Results

Discussion

Conclusion