A DATA MEMORY SYSTEM FOR A SEAFLOOR EARTHQUAKE MEASURING INSTRUMENT

Abstract

A Seafloor Earthquake Measurement System for measuring strong motion seismic data has been developed and tested by Sandia National Laboratories as part of the Department of Energy Offshore Instrumentation Program. The system’s function is to gather data for the design and regulation of offshore structures such as oil platforms and pipelines. The seafloor package is a self-contained unit capable of operating unattended for up to one year with data readout on command via an underwater acoustic telemetry system. One of the problems with such a system is the large memory required to store seismic data. This memory also must consume very little power to conserve battery life. To meet these conditions a combination low-power CMOS buffer memory and a one-million-bit magnetic bubble main memory with switched power was developed. This paper describes these memories and how they are controlled by a microprocessor to save the “best” data since the last data readout.