Abstract
The sand boils induced by the 2000 Western Tottori Earthquake (Mj7.3) widely occurred in reclaimed lands on the Yumigahama sand-bar, northwestern Tottori Prefecture, western Japan. It was observed at several locations that the sand boiling formed by liquefaction was continued for at least two days after the earthquake. This type of liquefaction is called “slow liquefaction” in this study. The gush height of boiled sands up to 90cm was directly observed at some locations. The ground of the sand boiled area has subsided 50cm in maximum. These phenomena will provide important information both for a quantitative evaluation of liquefaction potential of sand deposits and for a seismic hazard evaluation.
