Earth Planets Space, Vol. 56 (No. 12), pp. 1247-1252, 2004
Takeshi Sagiya1, Takuya Nishimura2, and Yoshihisa Iio3
1Graduate School of Environmental Studies, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
2Geographical Survey Institute, 1 Kitasato, Tsukuba 305-0811, Japan
3Disaster Prevention Research Institute, Kyoto University, Gokasho, Uji 611-0011, Japan
(Received June 13, 2004; Revised October 18, 2004; Accepted November 28, 2004)
We investigated the crustal deformation around the northern Itoigawa-Shizuoka Tectonic Line Fault Zone by continuous observation with a dense GPS array. The observation revealed concentrated deformation around the East Matsumoto-Basin Fault while the more active Gofukuji Fault has smaller strain rate. By examining the physical meanings of geodetic strain rate and the geological slip rate data, we estimate a larger seismic potential around the Gofukuji Fault. The deep slip model proposed for the strain concentration around the Omachi area was not validated. Inelastic deformation may play an important role as a cause of strain concentration.
Key words: Itoigawa-Shizuoka Tectonic Line Fault System, GPS, crustal deformation, strain concentration, tectonic loading.