Applicability of ESR dating using multiple centres to fault movement — The case of the Itoigawa-Shizuoka tectonic line, a major fault in Japan

Abstract

No direct method for dating the fault movement has been hitherto established, except ESR dating whose applicability is disputed however. The most serious question in ESR dating is whether accumulated ESR signals are completely reset at the time of fault movement. When the defect centres are partially preserved at the time of previous faulting, the date obtained is uncertain. We have shown (Fukuchi et al., 1985, 1986), however, that we can judge correctly whether ESR signals were completely reset or not when the ESR signal counting is done for multiple ESR centres of different stabilities for resetting. From the data for completely reset centres, actual date of fault movement can be calculated. This multiple centre method was tested with samples whose ESR signal intensities are judged to be about zero at the time of fault movement. The result, which confirms the applicability for the fault movement dated back to 100 ka BP, is presented in this paper.