Environmental geophysics: challenges and perspectives

Abstract

Modern civilizations are at risk from natural geophysical events and from industries whose accumulated wastes release toxic substances into the environment. These environmental hazards are increasingly man-made, increasingly voluntary and diffuse in their impact. Environmental geophysics addresses the quantification and monitoring of subsurface hazards, irrespective of their origin. There are two major challenges for environmental geophysicists, firstly, to understand socio-economic and environmental factors which govern the demand for their services and, secondly, to use improved methods and develop practices which more effectively address environmental problems. Field studies on major environmental problems provide some perspective on these challenges. Salinisation of agricultural lands is arguably Australia's major environmental problem. A dryland salinity study in Victoria demonstrates the process by which electromagnetic responses of soils can be expressed in terms of crop productivities for appropriate plant species. This information is of direct use to farmers, land managers and agronomists. Conventional geophysical methods have had limited success in delineating hydrocarbon LNAPL and DNAPL contamination, both major pollutants. In South Australia, the extent of a plume produced by a large diesel oil (LNAPL) spill was mapped with a new method of Radiowave electromagnetic profiling method (R-EM) which overcomes many of the limitations of conventional electromagnetic induction and ground probing radar methods. It is concluded that environmental geophysics has a bright future provided geophysicists are willing meet these challenges, if not, other non-specialists will increasingly enter the field as has been the case in North America.