Recent active fault research in Kyushu, southwest Japan

Abstract

Since Professor Tokihiko Matsuda had taken his post to Kyushu University, the active fault survey in Kyushu has progressed, and it has obtained much information on the active faults in Kyushu.
Kamegawa fault located in the eastern part of central Kyushu has investigat e d on 1997. It was a first trench survey on active fault in Beppu-Haneyama fault zone. Then active fault survey of Oita Prefecture has started in the Beppu-Haneyama fault zone, and it is continuing now. These surveys are the important investigations of the dense normal fault zone in Japan. By these surveys, it is sure to clarify the late Quaternary tectonics of central Kyushu.
In northern Kyushu, recent activity of Fukuchiyama fault inverted from the normal fault movement with mountainous area upheaval to the reverse-fault activity with upheaval of the plain. The trenching surveys of Nishiyama and Kego faults showed left strike-slip movements.
In southern Kyushu, Hitoyoshi basin south e rn margin fault was newly found as the fault bordered between mountain and alluvial fan in Hitoyoshi basin. The latest activity of the Izumi fault with characteristically right-lateral displacement was also clarified to predominate the normal faulting.