Inversion of Source Mechanisms for Single-Force Events Using Broadband Waveforms

Abstract

Abstract Source mechanism of a seismic event describes the kinematic process of the point source. In this article, we develop a CAPsf method to invert source mechanisms for single-force events, based on the generalized Cut-and-Paste algorithm. The CAPsf cuts broadband waveforms into body- and surface-wave segments and fits them independently to find the optimal force magnitude and direction, which are related to the volume and direction of the moving source, respectively. We apply the CAPsf method to the 10 October 2018 Baige landslide by the Jinsha River in Tibet to obtain the sliding direction and estimate its total volume. The result shows that the landslide slips approximately to the east with a dip angle of 36° and a total volume of 4.57×106∼1.90×107  m3. We also obtain the mechanism for initial source area of the 23 June 2017 Xinmo landslide using high-frequency body and surface waves. Both sliding directions and volumes inferred here agree with those measured from field observations, which validate our method.