Map of the major bathymetric features in the vicinity of the Solomon Islands region, showing the positions of OBSs. Contour interval is 250 m. Solid circles and numerals denote the positions of OBS and the OBS number, respectively. Outline of the Ontong Java Plateau and major plate boundaries are shown in the inset. The plate vector in the inset was calculated from NUVEL-1A (DeMets 1994) using a fixed India—Australia Plate.