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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

A drowned Holocene barrier spit off Cape Ann, Massachusetts A drowned Holocene barrier spit off Cape Ann, Massachusetts

Seismic profiles and bathymetric contours reveal a drowned barrier spit on Jeffreys Ledge off Cape Ann, Massachusetts. Seaward-dipping internal reflectors indicate that a regressive barrier formed during the early Holocene low sea-level stillstand. Preservation of the barrier spit may have been favored by its large size (as much as 20 m thick), by an ample sediment supply from...
Authors
Robert N. Oldale

Bottom current and sediment transport on San Pedro Shelf, California Bottom current and sediment transport on San Pedro Shelf, California

GEOPROBE (Geological Processes Bottom Environmental) tripods were used to measure bottom currents, pressure, and light transmission and scattering and to obtain time-series photographs of the sea floor at depths of 23 m and 67 m on San Pedro shelf between 18 April and 6 June 1978. Winds were light ( 5 m/s) with a mean direction from the southwest throughout the measurement period. Hourly...
Authors
David E. Drake, David A. Cacchione, Herman A. Karl

Occurrence and preservation of Eocene squamariacean and coralline rhodoliths: Eau, Tonga Occurrence and preservation of Eocene squamariacean and coralline rhodoliths: Eau, Tonga

A widespread rhodolith facies occurs within middle Eocene limestones of Eua, Tonga (Fig. 1). These limestones, first described by Hoffmeister (1932), represent a portion of a broad, early Tertiary platform that developed in the Tonga area prior to disruption and uplift by later Tertiary plate movements (Kroenke and Tongilava 1975). Algal rhodoliths form beds several meters thick within...
Authors
Binyamin Buchbinder, Robert B. Halley

Block Island fault: A Paleozoic crustal boundary on the Long Island platform Block Island fault: A Paleozoic crustal boundary on the Long Island platform

A major fault cutting through most of the crust can be identified and mapped on the Long Island platform using multichannel seismic reflection profiles and magnetic data. The fault, here called the Block Island fault (BIF), strikes north-northeast, dips westward at low angle, and does not resemble the thin-skinned thrust faulting observed in the foreland of the Appalachians. The BIF is...
Authors
Deborah R. Hutchinson, Kim D. Klitgord, R. S. Detrick

In situ stress, natural fracture distribution, and borehole elongation in the Auburn Geothermal Well, Auburn, New York In situ stress, natural fracture distribution, and borehole elongation in the Auburn Geothermal Well, Auburn, New York

Hydraulic fracturing stress measurements and a borehole televiewer survey were conducted in a 1.6‐km‐deep well at Auburn, New York. This well, which was drilled at the outer margin of the Appalachian Fold and Thrust Belt in the Appalachian Plateau, penetrates approximately 1540 m of lower Paleozoic sedimentary rocks and terminates 60 m into the Precambrian marble basement. Analysis of...
Authors
Stephen H. Hickman, John H. Healy, Mark D. Zoback
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