Dynamic Modeling of the 2020 Mw 6.0 Jiashi Earthquake: Constrained by Geodetic and Seismic Observations

Abstract

Abstract The 2020 Mw 6.0 Jiashi earthquake is the largest event recorded in the Jiashi region in the last 17 yr. Here we try to explore the primary characteristics of this event by using dynamic rupture modeling, and later compare our results with the Interferometric Synthetic Aperture Radar (InSAR) data and near-source ground-motion observations. To focus on the geometric effects of the seismogenic fault, we conduct spontaneous rupture simulations in a homogenous material by using a linear slip-weakening friction law. Our results show that the synthetic data fits well with the observations, including the InSAR data and strong ground-motion waveforms. Significantly, the low dip angle segments at both ends of the rupture area along the dip-slip direction have behaved as “stress barriers,” which stop the rupture propagation. In other words, the rupture could be arrested by the near-horizontal segments rather than being prevented by the steeper ramp proposed by the previous studies. Thus, our physics-based dynamic modeling shows how the fault geometry controls the 2020 Mw 6.0 Jiashi earthquake rupture. Our work contributes to understand the complex nature of the low dip angle listric-reverse fault.