[SCG57-P02] Three-dimensional plate geometry model from the Nankai to the Ryukyu subduction zone
Keywords:subducting plate, Nankai Trough, Ryukyu Trench
To understand relation between the structure around the subducting Philippine Sea plate and seismicity including slow earthquake phenomena, it is necessary to know the geometry and property of the plate boundary from the Nankai to the Ryukyu subduction zone. Three-dimensional plate geometry model will be also important for a precise estimate of the maximum range of the coseismic rupture zone of the Nankai megathrust earthquake. The model is also very useful to construct a new three-dimensional seismic velocity model of the Nankai Trough for depth conversion of interpreted active faults in time section of seismic reflection data [Katsuyama et al., 2019 JPGU].
Based on the result (three-dimensional plate geometry model of the Nankai Trough) from marine active and passive source seismic data [Nakanishi et al., 2018], three-dimensional plate geometry model from Nankai to Ryukyu subduction zone is tried to be constructed using the result of seismic studies around the Ryukyu Trench [Iwasaki et al, 1990; Kodaira et al., 1996; Arai et al., 2016, 2017; Nishizawa et al, 2017; Yamamoto et al., 2018].The model of Nakanishi et al.  is also updated by using the result of deep seismic tomography off the Kii peninsula [Yamamoto et al., 2014, 2017].
In this presentation, a preliminary version of the combined three-dimensional model will be shown.
This study is part of 'Research project for compound disaster mitigation on the great earthquakes
and tsunamis around the Nankai trough region' and the project 'Comprehensive evaluation of faults information on offshore Japan' funded by Ministry of Education, Culture, Sports, Science and Technology, Japan.