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An evaluation of the accuracy of geomagnetic data obtained from an unattended, automated, quasi-absolute station An evaluation of the accuracy of geomagnetic data obtained from an unattended, automated, quasi-absolute station

A comparison is made of geomagnetic calibration data obtained from a high-sensitivity proton magnetometer enclosed within an orthogonal bias coil system, with data obtained from standard procedures at a mid-latitude U.S. Geological Survey magnetic observatory using a quartz horizontal magnetometer, a Ruska magnetometer, and a total field magnetometer. The orthogonal coil arrangement is...
Authors
D.C. Herzog

What do we mean by accuracy in geomagnetic measurements? What do we mean by accuracy in geomagnetic measurements?

High accuracy is what distinguishes measurements made at the world's magnetic observatories from other types of geomagnetic measurements. High accuracy in determining the absolute values of the components of the Earth's magnetic field is essential to studying geomagnetic secular variation and processes at the core mantle boundary, as well as some magnetospheric processes. In some...
Authors
A.W. Green

Seismic-wave attenuation associated with crustal faults in the New Madrid seismic zone Seismic-wave attenuation associated with crustal faults in the New Madrid seismic zone

The attenuation of upper crustal seismic waves that are refracted with a velocity of about 6 kilometers per second varies greatly among profiles in the area of the New Madrid seismic zone in the central Mississippi Valley. The waves that have the strongest attenuation pass through the seismic trend along the axis of the Reelfoot rift in the area of the Blytheville arch. Defocusing of the...
Authors
R. M. Hamilton, Walter D. Mooney

Major off-axis hydrothermal activity on the northern Gorda Ridge Major off-axis hydrothermal activity on the northern Gorda Ridge

The first hydrothermal field on the northern Gorda Ridge, the Sea Cliff hydrothermal field, was discovered and geologic controls of hydrothermal activity in the rift valley were investigated on a dive series using the DSV Sea Cliff. The Sea Cliff hydrothermal field was discovered where predicted at the intersection of axis-oblique and axis-parallel faults at the south end of a linear...
Authors
Peter A. Rona, Roger P. Denlinger, M. R. Fisk, K. J. Howard, G. L. Taghon, Kim D. Klitgord, James S. McClain, G. R. McMurray, J. C. Wiltshire

The eruption of Redoubt Volcano, Alaska, December 14, 1989-August 31, 1990 The eruption of Redoubt Volcano, Alaska, December 14, 1989-August 31, 1990

No abstract available.
Authors
Thomas J. Casadevall, Bernard A. Chouet, John N. Davies, Steven A. Estes, Cynthia A. Gardner, Richard P. Hoblitt, John C. Lahr, Richard G. Lahusen, Jon J. Major, Robert G. McGimsey, Thomas P. Miller, Thomas L. Murray, Christina A. Neal, Christopher J. Nye, Robert A. Page, Thomas C. Pierson, John Power, Christopher D. Stephens, Richard B. Waitt

Origin of Florida Canyon and the role of spring sapping on the formation of submarine box canyons Origin of Florida Canyon and the role of spring sapping on the formation of submarine box canyons

Florida Canyon, one of a series of major submarine canyons on the southwestern edge of the Florida Platform, was surveyed using GLORIA, SeaBeam, and Deep-Tow technologies, and it was directly observed during three DSRV Alvin dives. Florida Canyon exhibits two distinct morphologies: a broad V-shaped upper canyon and a deeply entrenched, flat-floored, U-shaped lower canyon. The flat-...
Authors
Charles K. Paull, Fred N. Spiess, Joseph R. Curray, David C. Twichell
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