Fig. 3From: Dip distribution of Oita–Kumamoto Tectonic Line located in central Kyushu, Japan, estimated by eigenvectors of gravity gradient tensorHorizontal gravity gradient map. a Horizontal gravity gradient map of which all data are shown; the contour interval is 10 E (Eötvös: 1 E = 0.1 mGal/km). b Horizontal gravity gradient map of which areas of more than 25 E are shown by coloured contours; the contour interval is 5 EBack to article page