Abstract
A fault of the 1918 Omachi earthquake (M=6.5) have been estimated based on the vertical crustal movement associated with the earthquake. The 1918 Omachi earthquake was the largest earthquake which had ever occurred near the northern part of the Itoigawa-Shizuoka Tectonic Line (ISTL). The estimated fault is a high dip angle reverse fault with left lateral strike slip component. The fault plane strikes to the N-S and dips to the east. The fault model suggests a possibility that the Chikuma Mountains (Northeastern Japan) thrust against the Matsumoto Basin (Southwestern Japan).
