On 26th May 2010 Oxford Archaeology undertook a field impact assessment of geotechnical seismic survey investigations upon the potential archaeological resource at two trial locations north-east of Haslemere, Surrey. The investigation was undertaken in advance of, and to inform, a programme of geotechnical prospecting within the surrounding landscape. The survey utilised a 200g explosive charge buried 2 m deep into the underlying sediments. Controlled archaeological excavation and sampling of the discharged explosive at two locations established that these had a localised impact upon the surrounding sediment and that this was unlikely to significantly affect any archaeological remains. The explosive force created blast craters with diameters of c 0.65 m surrounded by areas of sediment compaction. The localised outcrops of ironstone found within the Weald Clay Formation were found to be resilient to the impacts of the blast. ©