Damage Distribution Map of Liquefaction Due to the 2013 Earthquake that Occurred Near Awaji Island

Abstract

This study reports on the liquefaction damages caused by the earthquake that occurred near Awaji Island, Hyogo Prefecture, on April 13, 2013;it also investigates the damage factors in Awaji City on the basis of an intensive field survey and a detailed ground data report on reclamation.　　
According to a detailed map of liquefaction obtained through the field survey, all liquefaction sites were located on reclaimed land and not on natural ground. At Ikuho-niijima, which has acquired the outline of reclamation, detailed ground data revealed that liquefaction occurred in the areas with loose sand deposit and high groundwater level in wells, a characteristic of reclaimed land, which in Awaji City tends to be young ground. On the basis of the field survey and detailed ground data report on reclamation, these findings strongly suggest that loose sand deposit and high groundwater level in wells are important factors for liquefaction, combined with earthquake motion.　Ground improvement of these lands benefited the prevention of liquefaction, and it is conjectured that this improvement is a regulation factor of liquefaction damage distribution.