Abstract
Field surveys and trench excavation investigations revealed that there were at least four large seismic events produced by slips on the Gosukebashi fault in the Holocene in the southeastern Rokko Mountains of Japan. The characteristics of deformed topographies and three‐dimensionally excavated exposures show that this fault is a right‐lateral strike–slip fault having an average slip rate of 1.0 mm/year, with a reverse displacement component. The principle indicators of past faulting events are: (i) termination of secondary faults; (ii) sedimentary deposits related to faulting; and (iii) injection veins of fault gouge related to seismic faulting in the fractured zone. Radiocarbon dates indicate that the events occurred pre‐1660 BC , 1660 BC –220 AD , from ∼ 30–220 to 600 AD and 15th century AD . The youngest event is probably associated with the large 1596 AD Keicho‐Fushimi earthquake which occurred in the area around Kyoto and Kobe Cities. The second younger event is probably correlated with the 416 AD Yamato earthquake, which is the oldest historic earthquake in Japanese historic records. The results of trench surveys show that the horizontal displacement produced by an individual event is ∼ 1.5 m, and the recurrence of seismic event intervals is ∼ 1200 years in the Gosukebashi fault.