Analysis of M 5.3 Sumbawa, Indonesia earthquake 2020 and its aftershocks based on hypocenter relocation from BMKG seismic stations

Abstract

The 2020 Sumbawa earthquake of moderate magnitude (M 5.3) produced very significant aftershocks. Based on the computation of Utsu’s method, those aftershocks would be ended after the 20th day. Those earthquakes along 20 days were relocated using double-difference method. The relocation results show the southwest-northeast orientation and getting deeper into the northwest direction. Those two directions show the strike and the dip from the fault plane of the earthquake which was consistent with the focal mechanism released by the Indonesian Agency for Meteorology, Climatology, and Geophysics (BMKG). Those results showed the majority of earthquakes occurred at a depth of shallower than 20 km. Those earthquake depths were fit with the previous study showing the crustal thickness beneath Sumbawa Island that was about 28 km. We also found that those earthquakes occurred at splay faults propagating to decollement structure. This study is beneficial for earthquake disaster mitigation especially in updating active faults on Sumbawa Island.

Hypocenter relocation of the Mw 5.9 eastern Manggarai earthquake 2022 and its aftershocks based on BMKG seismic network

“…A moderate earthquake (Mw < 6.0) which releases many aftershocks, has become the main attention of an earthquake event. A moderate earthquake followed by many aftershocks also IOP Publishing doi:10.1088/1755-1315/1227/1/012042 6 occurred in Plampang, Sumbawa, on June 13, 2020 [17,18]. The studies in this area indicate a very brittle zone along Sumbawa to Flores island.…”