Fig. 2

a Detailed bathymetry of the southwestern Ryukyu Trench. Cores PL04 and PC04 (red circle) were drilled in the north levee of the axial channel of the Ryukyu Trench floor. b Seismic reflection profile line 89 runs roughly N-S through the study area (red solid line in Fig. 1). Depth is represented as two-way travel time (TWT)