Active tectonics of the bottom of Lake Biwa and development of its lake basin, southwest Japan

Abstract

Lake Biwa, the largest and oldest lake in Japan, has existed in the Ohmi Basin since 5 Ma B.P. (Lower Pliocene time). Many active faults are densely distributed in and around this lake, and the destructive earthquakes in 1662, 1819 and 1909 were generated from these faults. It is inferred that the development of the basin of Lake Biwa has been closely connected with tectonic movement. This paper reveals the distribution and characteristics of sublacustrine active faults and explains the relationship between the development of the lake basin and the active tectonics of the bottom of Lake Biwa, on the basis of the interpretation of Uniboom records, air gun records and bathymetric charts of the bottom of the lake. -from English summary