Differentiating between the deposits left by tsunamis and storms remains a major challenge for the paleoseismology and paleotempestology communities. The coast of Shizuoka Prefecture, south central Japan, is impacted by both typhoons and by tsunamis triggered by great subduction zone earthquakes (M>8) along the adjacent Nankai Trough. Previous investigations along this coastline have reported abruptly emplaced sand layers interbedded between organic marsh deposits (Komatsubara et al., 2008). At Shirasuka, a narrow strip of low-lying land sandwiched between a beach ridge and the 60-70m high riser of the Middle Pleistocene Marine terrace (Tenpakubara terrace) is well-placed to record both types of deposits. At this site, fine-grained organic silt and clay deposition, beginning in the 13th century AD, has been repeatedly interrupted by coarse-grained overwash beach sand layers (Fujiwara et al., 2006). These sand sheets have been variously attributed to historical typhoons and tsunamis (Komatsubara et al., 2008); however, in part due to the plateau in the radiocarbon calibration curve, the precise correlation between sand layers and historical events remains unclear. We seek to resolve this uncertainty by applying both radiometric and luminescence-based dating approaches to the site. By constraining the timing of each sand layer, we seek to conclusively link geological evidence to known historical events and, in doing so, facilitate comparison between the different sedimentary expressions of these natural hazards in the coastal zone. Fujiwara, O., Komatsubara, J., Takada, K., Shishikura, M., Kamataki, T., 2006. Temporal development of a Late Holocene stran plain system in the Shirasuka area along western Shizuoka Prefecture on the Pacific coast of central Japan. Journal of Geography 115, 569-581. Komatsubara, J., Fujiwara, O., Takada, K., Sawai, Y., Aung, T.T., Kamataki, T., 2008. Historical tsunamis and storms recorded in a coastal lowland, Shizuoka Prefecture, along the Pacific coast of Japan. Sedimentology 55, 1703-1716.

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