Analysis of Paleo Tsunami by Luminescence Measurement of Beach Sand

Abstract

Luminescence measurements of coastal sand particles were applied to the analysis of paleo tsunami generated by a Japan Sea earthquake in 1833. Long-term coastal morphology was described for a 20 km sandy beach formed by fluvial sediments supplied from the Hinogawa River. The alongshore distribution of the thermoluminescence of beach sand and the comparison of shoreline in old maps indicated historical beach erosion at old river mouth and westward longshore sand transport. The vertical distribution of the optically-stimulated-luminescence of a sediment core sampled 420 m inland from the present shoreline suggested coastal and aeolian accretion processes interrupted by a 7 cm thick tsunami sediment layer. Numerical tsunami simulation supported the movement of beach sand due to flooding tsunami.