液状化リスク評価のための液状化被害と地形との関係性

─利根川中下流域・東京湾岸地域の被害を対象に─

抄録

 Many instances of liquefaction occurred throughout the lowlands of the Kanto Plain, central Japan following the 2011 off the Pacific coast of Tohoku Earthquake. In particular, serious liquefaction damage was concentrated at reclaimed land, such as at former river channels and lakes. This indicates the importance of referring to landform classification when making a liquefaction risk assessment. And, predictions of liquefaction risk should be based mainly on landform classification data. Liquefaction damage varies widely with differences in shallow geological conditions, even within the same landform classification. Liquefaction risk is assessed based on a finer micro landform classification created by adding forms calculated from DEM or by adding boring database sets. In addition, artificial modifications occurring within a short period, such as backfilling a site where gravel was removed, often affect liquefaction phenomena, and it is important to refer frequently to the history of an area.