Abstract
The Miboro Fault System or Shokawa Fault Zone extends for about 67 km along the upper course of the Shogawa River in the western Hida Mountains, central Japan. A trenching survey conducted by the Geological Survey of Japan in 1990 revealed that at least the Miogo Fault, a southern portion of the Miboro Fault System, might have ruptured in or after the 11th century. There is no direct evidence to indicate that the faulting event corresponds to the Tensho earthquake of 1586. However, villages damaged by landslide or slope failure associated with the Tensho earthquake are distributed along the Miboro Fault System. The distribution of damage, together with the above excavation survey result, suggests that the latest rupture event on the Miboro Fault System caused“ a Tensho earthquake” which severely affected Hida and northern Mino Districts.
