In this study, we investigated late Quaternary deep-sea sequences
of the C9001C cores to refine their tephrostratigraphy and
developed an improved marine terrace chronology along the Pacific
coast of northern Honshu. We first documented the presence of
tephras and cryptotephras by counting glass shards and heavy
minerals in samples from the cores. We then analyzed the chemistry
of shards and mineral grains to distinguish tephras from turbidites
(reworked or mixed tephra grains).We used these results to
establish a tephrostratigraphy based on the concentration of tephra
grains, enabling us to detect several important cryptotephras, and
then reassessed the reported ages of marine terraces to calculate
regional late Quaternary uplift rates.