To estimate the scale and feature of earthquake, the location and geometry of faults are important information. Japan Coast Guard conducted the seismic reflection survey in the focal area of the 1964 Niigata Earthquake in order to extract the location and geometry of faults in 2004, but tectonic geomorphological implications were not considered then. In this study the parameters of the multibeam echo sounder were estimated and the location and geometry of faults were extrapolated from the geographic map. They almost corresponded with the distribution of faults evaluated on the seismic reflection profile. More certain structural map was compiled from both results.

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