2019 Volume 14 Issue 4 Pages 353-361
In the 2018 Hokkaido Iburi Tobu Earthquake, a large-scale ground disaster caused by liquefaction occurred on embankments filled with volcanic ash soil in the Satozuka area of Sapporo City. Liquefied volcanic ash soil flowed through the ground with a gentle slope, spouted from the end of the slope, and the ground sank up to about 4 m deep. A similar phenomenon has occurred in the 2003 Tokachi-oki earthquake in the Kyowa area, Tanno Town close to Kitami City. In this report, in order to investigate the mechanism of the unique liquefaction damage occurred that the liquefied soil flowed out from the end of the sloping land, the comparison of the landform, the physical properties of the runoff and embankment material, the liquefaction characteristics, etc. of both sites were performed. As a result, it found that the old landform and the damage situation of both sites are very similar. In addition, it was found that the liquefaction resistance of the volcanic ash soil filled in the Satozuka area was very low compared to other volcanic ash soils in Hokkaido.
