Abstract
We conducted a trench excavation and array drillings on the northeastern part of the Eastern Ube fault, in order to reveal the fault activity in central-southern Yamaguchi Prefecture.
A fault thrown down to the southeast was found at the trench wall. By combining the trench survey results with previous studies, we showed that the latest and the penultimate events of the fault occurred in a period from 11,500 to 400 years ago and 38,000 to 20,000 years ago, respectively. Accordingly, the recurrence interval of the fault ranges from 8,500 to 37,600 years. No fault could be detected by the array drilling survey.
