Geophysical methods for the investigation of subsurface flows

Sammanfattning: Geophysical methods of investigating the substratum have been proven to provide quality data for a variety of applications. Despite this fact, such methods are not used in some fields to the degree that they could be. Reasons for this can include the complexity of the required measurements, the difficulties in interpreting the results, and a simple ignorance of the full potential of the various methods. One method that requires only very simple measurements with very little equipment is the self-potential or SP method, which can provide invaluable information concerning subsurface heat or liquid flows. This information could be used for example to track contaminants or to identify problem areas in or under an earth dam before they became serious. One difficulty with the SP method can be interpreting the results when the subsurface geology is complex. The first part of this thesis addresses this problem by creating a finite element computer program to model the streaming potential phenomenon for a complex domain with varying hydraulic, thermal and electrical conductivities. The second part of this thesis deals with a geophysical investigation of mining waste impoundments. Relatively simple electrical and electromagnetic methods are used to provide a thorough assessment of the impoundments' condition. Modern technological advances in both the measuring equipment and processing computers are seen to make the measurements faster and interpreting the results much easier.