Liquefaction on the Valley Filling Embankment Caused by the Tokachi-oki Earthquake in 2003, Hokkaido, Japan

Abstract

The liquefaction and slope disaster by The Tokachi-oki Earthquake (Mj8.0) on September 26, 2003, occurred at valley filling reclaimed farmland in Tanno-cho, Hokkaido. It is noticeable that a comparatively large liquefaction (about 6, 000-10, 000m³) occurred on the hill at 230km distant from the epicenter. It is presumed that mobilized sand (6, 000m³ or more) may be pressed out from several craters without downslope movement of the cave-in surface mass, and the cave-in accompanied by surface cracks arose after that. In this investigation, a field survey, aerial photo survey, airborne laser scanner survey and GIS analysis of land use were carried out and it is thought effective for distinction of artificial land form to use high-resolution DEM by airborne laser scanner survey.