Deep-Ocean Bottom Pressure Measurements in the Northeast Pacific

Pressure transducers with quartz-crystal resonators are being used to measure deep-ocean bottom pressure in the northeast Pacific as part of a long-term monitoring program. In principal, instrument sensitivity is less than 1 mm for sea-level oscillations of periods greater than a few minutes; in practice, however, system resolution is limited by long-term sensor drift and background noise. Data are digitally recorded at a rate of 64 samples per hour but selectable intervals ranging from 4 to 128 samples per hour are possible. The field program has focused on the maintenance of five permanent stations in the northeast Pacific since 1986. During this time, phenomena over a wide range of time scales have been recorded, including tides and the seismic surface waves and tsunamis generated by three earthquakes in the Alaskan Bight.