[S-SS15] Active faults and paleoseismology

[SSS15-06] Deformation of marine terrace surfaces associated with active Rokkasho fault in southern Shimokita peninsula, northern Japan

*Mitsuhisa Watanabe¹ (1.Faculty of Sociology, Toyo University)

Keywords:marine terrace, flexural scarp, bedding reverse fault, active fault

The marine terrace surfaces formed in MIS 5e and MIS 5c have successively deformed, resulting in a 1 km wide flexural scarp tilting to the east. These surfaces dipping to the same direction converged upon in the scarp. The flexure is consistent with the prevailing Neogene structure. Some bedding reverse faults are observed, which indicates that the structure is an active one. The marine terrace surfaces and the Tertiary system have been folded convincingly owing to the activity of west-dipping blind active thrust (the active Rokkasho fault), merging into the extensive submarine fault along shelf edge in the north.