Seismic detection of near-surface cavities

_________________________________________ _ Introduction ______________________________________ _ Methods of detection _______________________________ _ Free oscillations _______________________________ _ Anomalous amplitude attenuations _______________ _ Delays in arrival times _________________________ _ Page A1 1 2 2 4 4 Field studies ______________________________________ _ Signal enhancement_ _______________________________ _ Summary _________________________________________ _ References ________________________________________ _