Characteristics of the Seismogenic Faults in the 2018 Lombok, Indonesia, Earthquake Sequence as Revealed by Inversion of InSAR Measurements
Chisheng Wang, Xinyu Wang, Wenqun Xiu, Bochen Zhang, Guohong Zhang, Peng Liu
Abstract
Abstract We invert Interferometric Synthetic Aperture Radar observations for the slip models of the 28 July Mw 6.4, 5 August Mw 6.9, and 19 August Mw 6.9 earthquakes in the 2018 Lombok earthquake sequence. The geodetic measurements and aftershock distribution suggest three south-dipping fault planes with shallow depths for the three events. They are likely associated with the imbricate thrust faults above the main Flores fault. Obvious strike and dip differences were found on the seismogenic faults, which implies probable fault segmentation and explains the cascading fault behaviors with moderate magnitudes. The three events peaked at depths of 12.38, 16.9, and 25.9 km. The estimated moments reach 7.59×1018, 3.33×1019, and 4.61×1019 N·m, equal to Mw 6.52, Mw 6.95, and Mw 7.04 events, respectively. The derived slip distribution covers most of the area in the Lombok fault plane. Future seismic hazard on the seismic gap to the east of Lombok should be noted.