Gravity Survey in the District of Nishina Three Lakes, Nagano Prefecture, Japan

Abstract

Gravity survey was carried out in the district of Nishina Three Lakes which is located along the northern part of "Itoigawa-Shizuoka tectonic line". The gravity anomaly tends to decrease by about 20 mgal from the west to the east in this area. The rapid decrease in gravity anomalies is due to the vertical displacement of basement rock between both sides of Itoigawa-Shizuoka tectonic line.