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Microseismicity and Fault Structure in the Daliangshan Subblock Within the Southeastern Tibetan Plateau

Description: 

The Daliangshan subblock is located between the Tibetan Plateau and the South China block, characterized by intense tectonic deformation and complex fault structures. In this study, we analyze more than two years of continuous seismic records recorded by a recently deployed dense seismic array from December 2018 to April 2021. We used a recently developed machine learning-based earthquake location workflow (ESPRH) to construct a high-precision earthquake catalog for the region and obtained ~3000 earthquakes. Then, we mapped our final seismic location results to an existing S-wave velocity structure obtained through ambient seismic noise tomography. The seismicity distribution not only confirms the nature of the faults marked on the map but also delineates the detailed geometry of the unmapped faults. Earthquakes mainly occur at the boundaries of high- and low-velocity bodies or on high-velocity bodies, which is consistent with the tomography result. Combining the focal mechanism solution of historical earthquakes and the fault geometry of this paper, we also observed that the western side of the Daliangshan block is dominated by strike-slip faults, and the fault properties on the eastern side are complex. This tectonic phenomenon is attributed to the fact that during the lateral extrusion of the southeastern edge of the Chuandian fragments, the northeastern part of the Daliangshan subblock was squeezed by the South China block more strongly than its southwestern part was.

Session: Learning Across Geological, Geophysical & Model-Derived Observations to Constrain Earthquake Behavior [Poster Session]

Type: Poster

Date: 5/1/2024

Presentation Time: 08:00 AM (local time)

Presenting Author: Jin-zhi

Student Presenter: Yes

Invited Presentation: 

Authors