Geo-environmental applications

Abstract

Environmental applications of geophysical techniques concern the location, delineation and monitoring of subsurface, natural and man-derived hazards. Environmental geophysical surveys are concerned with the near surface, typically to depths of less than 30 m. Natural hazards include dissolution cavities, collapsing soils and earthquakes. Man-made hazards arise from the effects of pollution and previous land usage. Geophysical techniques may be applied in the assessment of the condition of derelict or contaminated land and the monitoring of remedial measures.The use of non-invasive geophysical methods is attractive where contamination is near the ground surface, as they do not penetrate any capping, which minimises the release of gas or the ingress of surface water. In some cases, to find contaminated zones within old landfills and derelict sites, geophysical surveys are the only practical method of investigation.9.1 INTRODUCTIONThe market for environmental geophysics has developed later in the UK than in the USA. Consequently, lessons learnt in the USA can be applied in the UK as activity here increases. In the USA, client confidence improved when it was understood that the geophysical methods used for environmental surveys were initially developed for the mining and petroleum sectors, but it was also recognised that there are special problems in environmental geophysics that require the development of new methods. Two aspects of environmental geophysics practice in North America (Steeples and Nyqyist, 1995; Bates, 1992; Danbom, 1995; Whiteley, 1995; Romig, 1992) that have relevance to the UK are: The encouragement of multi-method, multi-disciplinary surveys and trials.The recommendation for