The source mechanism analysis of significant local earthquake Mw 5.6 January 16, 2017 near Mt. Sibayak and Mt. Sinabung using moment tensor inversion of BMKG waveform data

Abstract

The source mechanisms of shallow tectonic earthquake Mw 5.6 on January 16, 2017 near Mt.Sibayak and Mt Sinabung was investigated by using moment tensor inversion. The result also compared by the field observation. We used waveform data from five BMKG station namely KCSI, PSI, LHMI, GSI, BKNI and one MY station namely IPM. Moment tensor inversion method is applied based on two aprroach spectral inversion and time domain inversion. We relocated mainshock and 29 aftershocks using HypoDD from waveform cross corelation method and also inversion 7 aftershocks with M<5. The Epicenter of relocated mainshock and aftershocks was investigated located near the Mount Sibayak and Mount Sinabung . The inversion result showed a mechanism of mainshock as strike-slip faulting with sinistral type, where the nodal plane of mainshock with strike/dip/rake (23/76/-1), Mw 5.8 and centroid depth is 18.9 km. The behaviour of this study is the distribution of relocated aftershocks oriented NNE-SSW were the same lineation with mainshock. Field observation show the damage building oriented to the NNW-SSE. As preliminary conclusion, the total Pressure (P) and Tension (T) axis from mainshock and aftershocks described dominant compression is happen from NNW and SSE.