Sonic prospecting and boring surveys of the Mikatagoko basins, Fukui Prefecture

Authors: Kiyohide Mizuno, Taku Komatsubara and Haruo Yamazaki (Tokyo Metropolitan Univ.)

Abstract: The Mikatagoko Basins in west Fukui Prefecture are believed to have been formed in relation to the movement of the Mikata fault system. We have conducted sonic prospecting and coring in two lakes named Suigetsu and Suga as well as boring surveys at four sites to clarify geologic structure of the basins. An N-S trending flexure has been recognized in the northern half of Lake Suga, and it is presumed that the east coast of Lake Suga has uplifted since the Late Pleistocene. The average subsidence rate in Lake Suigetsu is estimated at about 0.7 m/ky, which is larger than
the average vertical slip rate of the Mikata fault near Lake Kugushi (0.2-0.3 m/ky).

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