Fig. 1From: Lateral variation of the uppermost oceanic plate in the outer-rise region of the Northwest Pacific Ocean inferred from Po-to-s converted wavesOBS locations used in this study. a Red and yellow triangles indicate OBSs for active and passive seismic surveys, respectively. Orange dash line roughly represents the ridge line of the outer-rise region. Yellow stars indicate the locations where Pos waves tend to be weak toward the trench (see Fig. 4). b Zoomed-in map for box displayed in Fig. 1aBack to article page