Publications
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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 used with t
Authors
D.C. Herzog
Rheological analysis of fine-grained natural debris-flow material
Experiments were conducted on large samples of fine-grained material (???2mm) from a natural debris flow using a wide-gap concentric-cylinder viscometer. The rheological behavior of this material is compatible with a Bingham model at shear rates in excess of 5 sec. At lesser shear rates, rheological behavior of the material deviates from the Bingham model, and when sand concentration of the slurry
Authors
Jon J. Major, Thomas C. Pierson
Young volcanic deposits in the Valles Marineris, Mars?
A study of the interior deposits of the central Valles Marineris has led to the discovery of a sequence of deposits that cover the chasma floors and range in thickness from that of thin dust to several kilometers. The emplacement of the deposits was the last major event in the history of the Valles Marineris, following deposition of older layered interior beds, warping, faulting, erosion, and land
Authors
Baerbel K. Lucchitta
Summit Lake landslide and geomorphic history of Summit Lake basin, northwestern Nevada
The Summit Lake landslide, northwestern Nevada, composed of Early Miocene pyroclastic debris, Ashdown Tuff, and basalt and rhyolite of the Black Rock Range, blocked the upper Soldier Creek-Snow Creek drainage and impounded Summit Lake sometimes prior to 7840 yr B.P. The slide covers 8.2 km2 and has geomorphic features characteristic of long run-out landslides, such as lobate form, longitudinal and
Authors
B. Brandon Curry, W.N. Melhorn
Source parameters and effects of bandwidth and local geology on high- frequency ground motions observed for aftershocks of the northeastern Ohio earthquake of 31 January 1986
A 10-station array (GEOS) yielded recordings of exceptional bandwidth (400 sps) and resolution (up to 96 dB) for the aftershocks of the moderate (mb ≈ 4.9) earthquake that occurred on 31 January 1986 near Painesville, Ohio. Nine aftershocks were recorded with seismic moments ranging between 9 × 1016 and 3 × 1019 dyne-cm (Mw: 0.6 to 2.3). The two largest aftershocks (depth 5.3, 5.6 km; oblique righ
Authors
G. Glassmoyer, R. D. Borcherdt
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 applications of g
Authors
A.W. Green
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
Deep crustal structure of the Cascade Range and surrounding regions from seismic refraction and magnetotelluric data
Several regional seismic refraction and magnetotelluric (MT) profiles have been completed across the Cascade Range and surrounding geologic provinces in California, Oregon, and Washington. Analysis of three MT and two seismic refraction profiles in Oregon and a coincident MT and refraction profile in northern California show a high degree of correlation between resistivity and velocity models. The
Authors
William D. Stanley, Walter D. Mooney, Gary S. Fuis
Crustal structure of the northwestern Basin and Range Province from the 1986 Program for Array Seismic Studies of the Continental Lithosphere Seismic Experiment
A portion of northwestern Nevada was imaged to determine the crustal structure and to assess reported differences between refraction versus reflection determinations of Moho depth and how the crustal composition and structure has been influenced by volcanic and extension mechanisms. Interpretation of the refraction/wide-angle reflection data suggests that the crust is fairly uniform in thickness a
Authors
Harley M. Benz, R. B. Smith, Walter D. Mooney
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 waves in
Authors
R. M. Hamilton, Walter D. Mooney