It has come to be a common knowledge that active faults are the superficial expression of shallow earthquake generation. If this is true, such an active fault along or nearby which no shallow earthquakes have still been observed is thought to be an dangerous one which has high possibility of storing such a stress enough to generate a large shallow earthquake with long recurrent period in near future.
Basing upon such idea, the writers tried to clarify such active faults as above mentioned by composing the locations of historical earthquakes with an active fault map which had been completed in Japan excepting Hokkaido area. The locations of earthquakes are shown by horizontal area representing their earthquake volumes.
Geophysical and geological study should also be made for these kind of active faults.
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