Imaging of Initial Rupture Process of the 2016 Kumamoto, Japan, Earthquake
Abstract
We investigate the early rupture stage in the 2016 Kumamoto earthquake (Mw 7.0), which occurred on 15 April 2016 (UT) in Kumamoto region, central part of Kyushu Island, Japan, and during this event many building damages were reported in the near-source region. The source region includes the Futagawa fault and north part of the Hinagu fault, which are both active faults. The epicenter is near the junction between the two faults. We employ a source imaging technique (Takenaka et al., 2009, EPS) to the P-wave portion before the S-wave arrival of the waveform records observed at local seismic networks to map the radiation strength onto a possible rupture plane at sequential rupture time intervals. We apply this method to image the rupture process during 2.5 seconds after origin time in the initial rupture fault plane along north part of the Hinagu fault. From the imaged radiation strength, we found that the rupture starting at the hypocenter propagated on the initial rupture plane and reached near the shallower part of the junction between the Hinagu and the Futagawa faults than the hypocenter. The relatively large slip area then appeared near the junction part and spread southwestward on the initial fault plane although it did not overcome the junction during this initial rupture stage. It suggests that the shallower part of the junction worked as a barrier for the rupture at the initial rupture process and the rupture might have transfer to the main rupture plane, the Futagawa fault, from around a deeper part of the junction at the later stage.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2016
- Bibcode:
- 2016AGUFM.S53B2865T
- Keywords:
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- 7209 Earthquake dynamics;
- SEISMOLOGYDE: 7212 Earthquake ground motions and engineering seismology;
- SEISMOLOGYDE: 7223 Earthquake interaction;
- forecasting;
- and prediction;
- SEISMOLOGYDE: 7280 Volcano seismology;
- SEISMOLOGY