9712605 Dorman This ocean sciences instrumentation development project will develop and test an acoustic seismic source which uses hydrostatic pressure rather than explosives. The implosive device consists of a pressure case with a hole on one end. The hole is covered with a special ceramic plate prior to deployment. At depth, the plate is broken, causing an implosion, which in turn produces a low-frequency acoustic signal for use in seafloor research applications such as dealing with shallow shear velocity structures and short refraction profiles. Work to be performed involves engineering tests and at-sea trials to compare the acoustic signals from those from other types of sound sources. The proposed implosive device would be safer than explosives and would not be encumbered with regulatory restrictions.