The 2021 <i>M</i><sub><i>w</i></sub> 7.4 Madoi Earthquake: An Archetype Bilateral Slip‐Pulse Rupture Arrested at a Splay Fault
Kejie Chen, Jean‐Philippe Avouac, Jianghui Geng, Cunren Liang, Zhenguo Zhang, Zhicai Li, Shengpeng Zhang
Abstract
Abstract We combine measurements of ground deformation from Synthetic Aperture Radar images, high‐rate Global Navigation Satellite System and tele‐seismic waveforms to study the rupture kinematics of the Madoi Earthquake, which occurred in eastern Tibet on 21 May 2021 and reached a moment magnitude M w 7.4. The data show nearly pure left‐lateral motion along a 170 km long rupture and a total duration of 36 s. The earthquake initiated near the middle of the main segment and evolved in a bilateral slip pulse rupture which propagated at a sub‐Rayleigh speed of 2.6–2.8 km/s. In our model, slip is concentrated at depth of less than ∼15 km and reaches a maximum of 4.2 m. The rupture arrested ∼10 s after branching on the extensional splay faults at both extremities. The branching onto the splay faults and the eventual arrest of the rupture is used to provide constraints on the fault frictional properties.