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Causative Fault and Seismogenic Mechanism of the 2010 Suining M5.0 Earthquake in Sichuan Basin (China) from Joint Modeling of Seismic and InSAR Data

Description: 

Although the Sichuan basin in western China is a stable block with low historical seismicity, the Suining M5.0 earthquake on January 31, 2010 occurred near center of the basin, causing casualty and substantial damage. Previous studies have shown that the earthquake is very shallow and may occur in the sedimentary cover rocks, but its causative fault has not been identified. Based on local broadband seismic waveform data as well as a pair of ALOS PALSAR ascending orbit data, we exploresthe seismogenic mechanism via further constraining the source depth and the ruptured faul. The earthquake caused ground uplift in the southeast of the epicenter area, with maximum line of sight displacement of about 13.6 cm, much larger than the displacement caused by a M5 earthquake at typical depth of 10 km, which indicates that the earthquake is very shallow. Through joint inversion of seismic waveform and InSAR data, we obtain the moment magnitude of Suining earthquake as Mw4.5, with the strike, dip and rake of its fault plane as 17°, 66° and 90° respectively, and the centroid depth less than 1 km, supporting that the earthquake occurred at the shallow part of a high angle thrust fault dipping to southeast. It is further confirmed that the earthquake may be triggered by the diffusion of high-pressure fluid migrating from the underside gas reservoir.

Session: Understanding and Managing Induced Seismicity

Type: Oral

Date: 4/19/2023

Presentation Time: 09:00 AM (local time)

Presenting Author: Wangwang Gu

Student Presenter: No

Invited Presentation: 

Authors