Refining slip distribution in moderate earthquakes using Sentinel-1 burst overlap interferometry: a case study over 2020 May 15Mw 6.5 Monte Cristo Range Earthquake

Abstract

SUMMARYAzimuth and range measurements from Synthetic Aperture Radar (SAR) images are commonly used to depict the coseismic deformation of large earthquakes. Azimuth measurements associated with moderate-sized earthquakes are hardly applicable due to their limited accuracy. In this paper, we first explored the capability of Sentinel-1 azimuth measurements to map the coseismic deformation of a moderate earthquake. We used both range and azimuth offset measurements to map the coseismic deformation of the 2020 Mw 6.5 Monte Cristo Range earthquake in Nevada. Optimal dip angles of the two main faults and the slip model were obtained. By adding azimuth displacements as constraints, the inverted slip model reveals shallower and more refined slip than models only constrained by InSAR and GPS data, highlighting the importance of introducing the azimuth measurements to the moderate earthquake. The preferred fault model shows a mixture of left-lateral and normal faulting on the western segment and a left-lateral slip on the eastern segment. We found that the inferred faults might verify the clockwise rotation block model, which has been proposed to accommodate fault slip across the Mina deflection. Moreover, a shallow alluvial basin and the young left-lateral fault within the left bend can potentially be responsible for the orientation and normal slip components in the western fault segment, respectively.