[S-SS30_29PO1] New perspective of great earthquakes along subduction zones

[SSS30-P26] A structural traverse across the Shimanto belt in western Shikoku, Japan

*Kiyokazu OOHASHI¹, Kyuichi KANAGAWA¹ (1.Graduate School of Science, Chiba University)

Keywords:Shimanto accretionary complex, Out of sequence thrust, Melange, Vitrinite reflectance, Fault rocks

The Cretaceous and Tertiary Shimanto accretionary complex is largely characterized by imbricated thrust slices of trench-fill and ocean-floor sediments, and is thought as an ancient analog of the Nankai accretionary prism. Recent studies on a thermal structure and fault rock analysis for the Shimanto accretionary complex in the central and eastern Shikoku revealed that it has suffered earthquake faulting along the out-of-sequence thrusts associated with tectonic uplift. However, special distributions of thermal and tectonic structures are remaining unclear since those in the western part of Shikoku are poorly understood. In the presentation, we demonstrate the distributions and details of deformed rocks (e.g. melange and brittle faults), geological structure, and vitrinite reflectance across the Shimanto belt in western Shikoku.