A GENERAL EARTHQUAKE-OBSERVATION SYSTEM (GEOS)

Microprocessor technology has permitted the development of a General Earth-quake-Observation System (GEOS) useful for most seismic applications. Central-processing-unit control via robust software of system functions that are isolated on hardware modules permits field adaptability of the system to a wide variety of active and passive seismic experiments and straightforward modification for incorporation of improvements in technology. Various laboratory tests and nu-merous deployments of a set of the systems in the field have confirmed design goals, including: wide linear dynamic range (16 bit/96 dB); broad bandwidth (36 hr to 600 Hz;>36 hr available); selectable sensor-type (accelerometer, seismo-meter, dilatometer); selectable channels (1 to 6); selectable record mode (contin-uous, preset, trigger); large data capacity (1.4 to 60 Mbytes); selectable time standard (WWVB, master, manual); automatic self-calibration; simple field oper-ation; full capability to adapt system in the field to a wide variety of experiments; low power; portability; and modest costs. System design goals for a microcom