Fig. 1
From: Geoelectrical evidence of fluid controlling slow and regular earthquakes along a plate interface
Study location and bathymetry of the Hyuga-nada region. (a) Regional bathymetry. The orange star denotes the Kakioka Geomagnetic Observatory Station of the Japan Meteorological Agency. (b) Observation array and fault rupture areas. Red circles denote marine ocean bottom electro-magnetometer observation sites. Sky-blue dotted lines are the depth contours of the plate boundary interface66. The turquoise bold dotted line denotes where the Kyushu–Palau Ridge is subducting29. Granite areas known from terrestrial geological surveys are shown in magenta67. Solid blue lines indicate the slip areas of the 1946 Nankai68 and the 1968 Hyuga-nada25 earthquakes. Blue stars denote regular earthquakes (> M7.0) determined by the Japan Meteorological Agency. The orange contours show the total cumulative slip of long-term SSEs (contour interval 20 cm) from 1996 to 201727. The yellow crosses denote the shallow tremors generated from May to July 201326. The purple solid arrow indicates a convergence direction of the Philippine Sea Plate toward the Amurian Plate.
