The Development of a Seafloor Earthquake Measurement System

A Seafloor Earthquake Measurement System is being developed at Sandia to measure marine sediment response to seismic activity. The system will use an acoustic telemetry system to transmit commands to and collect data from the seafloor package. The seafloor package contains a microprocessor which controls the data collection, data processing, and acoustic telemetry. A one million bit magnetic bubble memory is used for storage of seismic data obtained from a three-axis accelerometer package. The microprocessor continuously compares the incoming data in mass memory and saves the "best" data for later readout by the acoustic telemetry system. The seafloor package consists of a ballast emplaced pressure vessel and probe containing the accelerometer. After the probe is inserted into the sediment, the ballast weight is removed and a section of the probe is retracted to mechanically isolate the accelerometers.