Kitatake fault and the neogene deposits in the nobi area yokosuka city south central japan
Kanie, Y.; Ota, Y.
Science Report of the Yokosuka City Museum 38: 25-28
The WNW-ESE-trending Kitatake Fault, is one of major active faults in the Miura Peninsula, south Kanto, and marks geological and topographical boundaries. In the Nobi area, eastern part of the Kitatake Fault, dissected hillylands up to 116 m in altitude are composed of the Miura Group to the northwest of the fault, while to the southwest, low hillylands up to 77 m are underlain by the Hayama Group. Long term vertical slip-rate is 0.1-0.4 m/ka, but it attains to 1.7 m+/ka for the last 6000 years. Right-lateral offset along the fault is more predominanted displacement and sliprate is 2-4 m/ka. No creeping has been observed along this fault. The Kitatake Fault consists of two or more parallel faults with a fault zone ranging 20-80 m in width. The Zushi Formation of the Miura Group is distributed on the northeast and undivided Hayama Group on the southwest with the Tateishi Tuff Member of the Abuzuru Formation in the Hayama Group in between. The age of the respective formations is correlated with Late Miocene (by CN9a calcareous nannoplankton subzone), early Middle Miocene (by CN4 nannoplankton zone) and late Early Miocene to early Middle Miocene (by radiolarian zone).