09:30 〜 09:45
[SSS06-03] Centroid moment tensor analysis of waveform data from ocean bottom seismometers by using 3-D seismic velocity structure
★Invited Papers
キーワード：セントロイド・モーメントテンソル、海底地震計
It is important to determine focal mechanisms of earthquakes for investigating stress fields in subduction zones. Stress changes after large earthquakes help understand the earthquake generation mechanisms and the state of mechanical coupling between the subducting and overriding plates. Tectonic stress fields and such stress changes have been estimated from stress orientations obtained from focal mechanisms (e.g., Terakawa and Matsu’ura, 2023). Increase of the spatial and temporal densities and resolutions of the focal mechanisms has a potential to increment those of the stress fields.
One of the ideas to obtain more focal mechanisms is to conduct centroid moment tensor inversion using waveform data from ocean bottom seismometers. Recently, ocean bottom seismometer networks of both temporary and permanent deployment have been developed along subduction zones (e.g., Cascadia Initiative: Toomey et al., 2014; DONET: Kaneda et al., 2015; S-net: Kanazawa et al., 2016.). However, most studies using short-period OBSs have only extracted information of the phase arrivals such as travel time and amplitude polarity. Recent developments of constructing 3-D high-resolution seismic velocity structure models and calculating synthetic waveforms using 3-D models enable us to analyze waveform data from ocean bottom seismometers (Yamaya et al., 2022), which have a potential to reveal tectonic stress field in subduction zones.
One of the ideas to obtain more focal mechanisms is to conduct centroid moment tensor inversion using waveform data from ocean bottom seismometers. Recently, ocean bottom seismometer networks of both temporary and permanent deployment have been developed along subduction zones (e.g., Cascadia Initiative: Toomey et al., 2014; DONET: Kaneda et al., 2015; S-net: Kanazawa et al., 2016.). However, most studies using short-period OBSs have only extracted information of the phase arrivals such as travel time and amplitude polarity. Recent developments of constructing 3-D high-resolution seismic velocity structure models and calculating synthetic waveforms using 3-D models enable us to analyze waveform data from ocean bottom seismometers (Yamaya et al., 2022), which have a potential to reveal tectonic stress field in subduction zones.