9505730 STEPHEN This renewal award supports development of instrumentation for deploying seismometers in the deep ocean at a hole (OSN-1) drilled by the Ocean Drilling Program near the island of Hawaii. The overall objective is to enable measurement of seismic activity accurately and over long periods at ocean bottom sites, to fill major gaps in recording worldwide earthquake activity which is primarily limited to land measurements. With their previous award, these Woods Hole Oceanographic Investigators, in collaboration with colleagues at Scripps Institution of Oceanography, have prepared and tested (in a test well on land) a seismograph system suitable for installation in a borehole. In the present work they will prepare a suitable housing for the seismometer to withstand deep- ocean pressures, and will design and build equipment to install the seismograph and data recording package in the ocean bottom borehole from a ship at the sea surface.