Seismogenic structure along the deformation front off SW Taiwan revealed by the aftershocks of the 2017 Tainan near-shore earthquake with ocean bottom seismometers

Located in the northern end of the Manila Trench, the deformation front (DF) off southwestern Taiwan is considered as a potential area for generating hazardous earthquakes and tsunamis. However, this area has been relatively seismically quiet, and the seismogenic structure has been unclear, particularly in the middle-to-lower crust. On February 10, 2017, an Mw5.3 earthquake occurred in the near-shore area of Tainan in SW Taiwan, which provides us with a good opportunity to study the seismogenic structure of this area. Five ocean bottom seismometers (OBSs) were deployed to cover the mainshock source area from February 13 to March 1, 2017, to record the aftershock data. All the OBSs were successfully recovered and, the P- and S-wave arrival were manually identified. In collaboration with arrival times from the Central Weather Bureau of Taiwan, we simultaneously determined the 1-D optimal Vp and Vs velocity models and hypocenter locations. The inversion results show that the upper crust (