Fig. 5From: Continuity of subsurface fault structure revealed by gravity anomaly: the eastern boundary fault zone of the Niigata plain, central Japan a Map of the first horizontal derivative (HD). Areas over 4.5 mGal/km are colored by red. b Map of the first vertical derivative (VD). Zero isoline is shown by gray line. Precisely located and inferred active faults are indicated by black solid and dashed lines, respectively (Nakata and Imaizumi 2002)Back to article page