Open AccessBayesian Inference of Centroid Moment Tensors of the 2019 Ambon (Mw 6.5) Aftershock Earthquake Sequence, Indonesia: A Preliminary Result
Author(s) -
Aria Widhi Baskara,
David P. Sahara,
Andri Dian Nugraha,
Abdul Muhari,
Andi Azhar Rusdin,
Shindy Rosalia,
Awali Priyono,
Zulfakriza Zulfakriza,
S Widiantoro,
Nanang T. Puspito,
Aditya Lesmana,
Dian Kusumawati,
A. Ardianto,
Yehezkiel Halauwet
Publication year - 2021
Publication title -
iop conference series. earth and environmental science
Language(s) - English
Resource type - Journals
eISSN - 1755-1307
pISSN - 1755-1315
DOI - 10.1088/1755-1315/873/1/012022
Subject(s) - aftershock , sinistral and dextral , seismology , geology , focal mechanism , moment tensor , centroid , strike slip tectonics , induced seismicity , fault (geology) , geodesy , geometry , oceanography , deformation (meteorology) , mathematics
The Ambon Mw 6.5 earthquake on September 26th, 2019, had contributed to give severe damages and significantly increased seismicity around Ambon Island and surrounding areas. Mainshock was followed by aftershocks with spatial distribution added to the impact of destructions in this region. We investigated aftershocks sequences to reveal the effect of mainshock toward the change in the in-situ stress field, including the possibility of the existing faults reactivation and the generation of aftershocks. We inferred centroid moment tensor (CMT) for significant aftershock events with Mw more than 4.0 using waveform data recorded from October 18th to December 15th, 2019. The aftershock focal mechanism was determined using the Bayesian full-waveform inversion code ISOLA-Obspy. This approach provides the uncertainty of the CMT model parameters. From ten CMT solution we had inferred in three seismic clusters, we found that majority of events have a strike-slip mechanism. Four events located on the south of the N-S trendings have a dextral strike-slip fault type, reflected the rupture of the mainshocks fault plane. Three events in the cluster of Ambon Island are dextral strike-slip, confirming the presence of the fault reactivation. Meanwhile, three CMT solutions in the north show the dextral strike-slip faulting and may belong to the mainshock main fault, connected with the cluster in the south.