Abstract: The Hinagu fault system extends for about 75 km from northeast to middle of Kumamoto Prefecture in Kyushu, western Japan. It consists of the Futagawa-Kitamukiyama fault in the northern part and the Hinagu fault in the southern part. The former is 20 km long and strikes N60°E, and the lat ter is 55 km long and strikes N30°E. We conducted boring and trench survey s at two localities on the Hinagu fault. The survey at Takagi has revealed that the latest activity of the northern part of the Hinagu fault occurred 1,300-1,500 ¹⁴C yBP. The horizontal displacement associated with the latest activity is 2.2 m right laterally and vertical one is not considerable. On the other hand, the survey results at Kakoi indicate that the last rupture on the southern part of the Hinagu fault occurred 2,000-7,400 ¹⁴C yBP, and its vertical displacement amounted to about 3 m. Kumamoto Prefecture (1996) has revealed that the last rupture on the
Futagawa-Kitamukiyama fault occurred earlier than 6,000 ¹⁴C yBP. From these paleoseismological data, it is concluded that the Hinagu fault system is divided into three behavioral segments; the Futagawa, northern Hinagu, and southern Hinagu segments.

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