An application of multi-channel analysis of surface waves (MASW) to hydrological study: A case history

Abstract

The multi-channel analysis of waves (MASW) is a seismic survey method, in which the seismic data are analysed in the frequency-phase velocity domain to estimate underground S-wave velocity structure. It is used in a variety of engineering projects from large to small at various stages. An MASW survey was carried out to investigate palaeochannels which is suspected to provide passage to leakage of a dam. For the condition peculiar to the dam site, three different methods of data acquisition were used: spiked geophones; landstreamers and unspiked geophones supported by play dough. These methods of placing geophones provided comparable data quality. The result was presented in section form along the survey lines and interpolated depth slices in plan view of S-wave velocity distribution. The plan view maps showed a pattern of low S-wave velocity anomaly which is interpreted as drainage. This result was correlated with the other geotechnical tests and used in the subsequent hydrological study.