Fig. 1

Shaded relief map of the Atotsugawa fault system and surrounding region. The black lines indicate active faults. The Atotsugawa fault (ATF), Mozumi–Sukenobu fault (MSF), and Ushikubi fault (UKF) comprise the Atotsugawa fault system. Yellow circles indicate GEONET stations. Red circles indicate our GNSS stations used for correcting the interferograms. Blue circles indicate our GNSS stations not used for corrections. GEONET station 0250 was used as the reference. The red frame indicates the area shown in Figs. 5 and 7. Active volcanoes appear as triangles. The inset shows the location of the study area (black frame) within the Japan arc. The blue line indicates the Niigata-Kobe Tectonic Zone (NKTZ)