Identification of landslide and its characteristics on the seafloor around Japan using anaglyph images.

Abstract

The distribution of subsolifluction （landslide and slope failure） along the Japan Trench, the Sagami Trough, the Suruga Trough, the Nankai Trough and the Sea of Japan is identified by 3D-image interpretation analysis using anaglyph images derived from digital bathymetry model with 90-m resolution. In order to understand the occurrence factor,（ 1） the original slope of subsolifluction is restored and the distribution of slope angle is compared with surrounding slopes, （2） the relation between area of subsolifluction versus frequency is discussed from a viewpoint of power-law model and （3） the location of subsolifluction is investigated with distribution of active faults. The result shows that the incentive factor of strong ground motion by earthquakes contributes more to large subsolifluction than the basic factor of slope angle.