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A wide range of geophysical techniques is applied in forensic investigations where the target objects are frequently buried under ground and are often small in size. These include targets which are only a few centimetres in diameter but located within a large search area are often of several hectares. The application of a specific geophysical technique may be governed by the physical properties of the target object and its local surroundings. However, operational and financial costs are important. Topographical and geological variations or presence of man-made structures may hinder the application of the most cost-effective technique. Additionally, site area, logistics and weather conditions are also important factors.Generally, to overcome these difficulties it is recommended that forensic geophysics be carried out along conventional geophysical guidelines as used in civil-engineering site investigation. On occasion, departure from these conventional guidelines may be beneficial in that field survey data acquisition can be complemented by simultaneous direct invasive assessment of geophysical anomalies instead of waiting until office reporting has been completed. Three case studies are presented: one relates to a search for a buried metal target located using a scanning magnetometer with simultaneous excavation, and two relate to searches for graves and buried wooden coffins

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Rock excavation conditions at engineering construction sites such as roads and pipeline routes can be assessed from a measurement of the seismic P-wave velocity. From a knowledge of the seismic velocity it is possible to establish where blasting may be required along the route rather than conventional excavation procedures. The popular term 'ripping' is applied to excavation without blasting and manufacturers of excavation equipment have produced charts relating the rippability of a rock mass to its measured in situ seismic velocity. These charts are a basic guide to the assessment of rippability and cover a limited range of rock types; in addition, they do not always include the effects of weathering or the degree of stress relief in the rock mass resulting from removal of the overburden.The effectiveness of the use of seismic velocity measurements for predicting rippability is examined. It is shown that, provided each lithological type is considered, in conjunction with an assessment of the degree of fracturing and weathering in the rock mass and an appraisal of the effects of stress relief, then seismic velocity is a valuable parameter for predicting rippability. This can lead to a consequent reduction in costs due to the decreased use of blasting.