Kutcharo Pyroclastic Flow Deposits V, IV, and I near Abashiri
K. Okumura  Tephrochronology, correlation, and deformation of marine terraces in eastern Hokkaido, Japan. Geographical Report of Tokyo Metropolitan University, 31, 19--26.
[Abstract] Tephrochronology of Akan, Kutcharo and intercalating exotic marker tephras innovated the chronology and correlation of Middle to Late Pleistocene marine terraces in eastern Hokkaido The vertical displacement of M1 and older paleoshorelines along the Okhotsk Sea indicates two distinctive uplift zones of Abashiri and Shiretoko. On the Pacific coast, respective gentle eastward tilting and westward bending in the east and in the west of Abashiri tectonic line evidence active thrusting beneath. The westward shift of the Kurile forearc sliver accounts for the thrusting at the Abashiri tectonic line in the outer Kurile arc and the growth of dextral en echelon ridges in the inner arc.
FIGURE 1 Distribution of Late Pleistocene marker tephras
Late Pleistocene tephra section near Abashiri. KPIV to KP I and above including exotic marker tephras of Spfa-1, Aso-4, Toya.
Severely disturbed Spfa-1 [yellow layer in the middle: 35 to 40 ka] underlain by phreato-plinian pumice and ash fall layers proceeding KP I east of Abashiri. The disturbance is owing to cold climate during the Glacial age.
Marine terraces in northern Japan. The former shoreline of each terrace indicates vertical crustal movement since its formative age.
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