Surface-wave survey at a ground cave-in site in Abira town, Hokkaido

Abstract

Subsurface cavities located deep underground potentially cause large-scale cave-ins. Radar survey has been applied to detect cavities in shallow ground with high accuracy, whereas there is no effective non-destructive exploration method for cavities deeper than 2m below the ground surface. In this research, surface wave survey, which is a method to estimate the S-wave velocity structure deep underground, was conducted at a cave-in site in Abira town, Hokkaido. It was confirmed that surface wave survey is an effective method for detecting loosening regions which become cavities later, and for estimating water channels which may cause cave-ins.