Crustal deformation around the northern and central Itoigawa-Shizuoka Tectonic Line

Abstract

We established a dense permanent GPS array around the northern and central Itoigawa-Shizuoka Tectonic Line (ISTL) in order to study loading processes of inland active faults. 1-4 years observation has revealed concentrated deformation (about 0.3 ppm/yr) around the East Matsumoto-Basin Fault, an active fault along the ISTL, consistent with historic triangulation data. The deformation pattern is explained by dislocation models incorporating horizontal detachment fault with steady slip in the upper crust. However, deformation data alone cannot determine the model and there exist different possibilities. The vicinity of the Gofukuji fault is being deformed less in spite of the large long-term slip rate. These observations indicate that the deformation pattern is laterally heterogeneous along the ISTL. The two faults are considered to be loaded by different mechanisms. Copyright © The Society of Geomagnetism and Earth, Planetary and Space Sciences (SGEPSS); The Seismological Society of Japan; The Volcanological Society of Japan; The Geodetic Society of Japan; The Japanese Society for Planetary Sciences.