Sites YG-1 to YG-6 were in the Nakahama Range and sites YG-7 and YG-8 were in the Sotohama Range.
However, there have been few attempts to assess the use of post-IR IRSL for dating Holocene sediments in Japan.
The GPR data were processed with Reflexw software (Sandmeier Scientific Software, Karlsruhe, Germany). The samples were taken from the bottom of auger holes of at least 90 cm depth so that surface disturbances were avoided.
Data processing included dewow filtering, zero-time correction, time-depth conversion, and static correction. (Tokyo Peil) is the standard datum for elevation measurements in Japan. A light-tight stainless-steel tube (30 cm long, 6.5 cm inside diameter) was hammered into the bottom of each borehole to extract samples of sand that had not been exposed to light.
Thus, the depositional age of the samples should young seaward (from YG-1 to YG-8).
Sample preparation and luminescence measurement were done at the luminescence laboratory of the Geological Survey of Japan.