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A general earthquake-observation system (GEOS) A general earthquake-observation system (GEOS)

Microprocessor technology has permitted the development of a General Earthquake-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...
Authors
R. D. Borcherdt, Joe B. Fletcher, E.G. Jensen, G.L. Maxwell, J.R. VanSchaack, R.E. Warrick, E. Cranswick, M.J.S. Johnston, R. McClearn

Monitoring the hydrothermal system in Long Valley caldera, California Monitoring the hydrothermal system in Long Valley caldera, California

An ongoing program to monitor the hydrothermal system in Long Valley for changes caused by volcanic or tectonic processes has produced considerable data on the water chemistry and discharge of springs and fluid temperatures and pressures in wells. Chemical and isotopic data collected under this program have greatly expanded the knowledge of chemical variability both in space and time...
Authors
C. D. Farrar, M.L. Sorey

Crustal structure of the southern Calaveras fault zone, central California, from seismic refraction investigations Crustal structure of the southern Calaveras fault zone, central California, from seismic refraction investigations

A magnitude 5.7 earthquake on 6 August 1979, within the Calaveras fault zone, near Coyote Lake of west-central California, motivated a seismic-refraction investigation in this area. A northwest-southeast profile along the fault, as well as two fan profiles across the fault were recorded to examine the velocity structure of this region. The analysis of the data reveals a complicated upper...
Authors
Peter Blumling, Walter D. Mooney, William H. K. Lee

Ferromanganese crusts from Necker Ridge, Horizon Guyot and S.P. Lee Guyot: Geological considerations Ferromanganese crusts from Necker Ridge, Horizon Guyot and S.P. Lee Guyot: Geological considerations

Necker Ridge, Horizon Guyot and S.P. Lee Guyot in the Central Pacific were sampled, seismically surveyed, and photographed by bottom cameras in order to better understand the distribution, origin, and evolution of ferromanganese crusts. Necker Ridge is over 600 km long with a rugged crest, pods of sediment to 146 m thick, slopes that average 12° to 20°, and debris aprons that cover some...
Authors
James R. Hein, Frank T. Manheim, William C. Schwab, Alice S. Davis
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