Publications
Filter Total Items: 7487
Vertical seismic profiling of Oroville microearthquakes: Velocity spectra and particle motion as a function of depth Vertical seismic profiling of Oroville microearthquakes: Velocity spectra and particle motion as a function of depth
Direct evidence of site distortion of P- and S-wave microearthquake source spectra at Oroville, California, is presented. The data were gathered by placing vertical and three-component seismometers at 90 m intervals in a 500 m borehole through the Cleveland Hill normal fault, on which the 1975, ML = 5.7 Oroville earthquake took place. High-pressure, hydraulic locking mechanisms were used...
Authors
P. E. Malin, J. A. Waller, Roger D. Borcherdt, E. Cranswick, Edward G. Jensen, J. Van Schaak
Friction of ice Friction of ice
The frictional strength of ice seems to be well below that for all other rocks. Triaxial testing of cylinders of pure water ice containing a 45° inclined sawcut, at temperatures of 77 ≤ T ≤ 115 K and confining pressures 0.1 ≤ P ≤ 250 MPa, reveals the frictional laws τ = 0.20 σn + 8.3 MPa for P ≥ 10 MPa and τ = 0.55 σn + 1.0 MPa for P ≤ 5 MPa, where τ and σn are the shear and normal...
Authors
M. L. Beeman, W.B. Durham, Stephen H. Kirby
Numerical analysis of Landsat Thematic Mapper images of Antarctica Numerical analysis of Landsat Thematic Mapper images of Antarctica
Landsat-5 Thematic Mapper (TM) data from Dronning [Queen] Maud Land, Antarctica, have been analysed to provide insights into physical properties of the ice sheet. Brightness (at-satellite) temperatures calculated from digital numbers of the thermal band (TM band 6), using state-of-the-art equations and constants (Markham and Barker 1986), are 8° to 20°C lower than temperatures measured...
Authors
Olav Orheim, Baerbel K. Lucchitta
Recording strong motion studies Recording strong motion studies
Instruments now permit strong‐motion signals to be recorded over broader band widths, with wider dynamic range and signal resolution and with better data accessibility via computer. These advantages are utilized by the General Earthquake Observation System (GEOS) developed by the United States Geological Survey, by which a microcomputer‐controlled system provides improved strong‐motion...
Authors
Roger D. Borcherdt
Large quaternary landslides in the central appalachian valley and ridge province near Petersburg, West Virginia Large quaternary landslides in the central appalachian valley and ridge province near Petersburg, West Virginia
Geological mapping and photointerpretation of side-looking airborne radar images and color-infrared aerial photographs reveal two large Quaternary landslides in the Valley and Ridge province of the central Appalachians near Petersburg, W. Va. The Elkhorn Mountain rock avalanche occurs on the thrust-faulted northwestern flank of the Elkhorn Mountain anticlinorium. A minimum of 7 × 106 m3...
Authors
C. Scott Southworth
The geometric signature: Quantifying landslide-terrain types from digital elevation models The geometric signature: Quantifying landslide-terrain types from digital elevation models
Topography of various types and scales can be fingerprinted by computer analysis of altitude matrices (digital elevation models, or DEMs). The critical analytic tool is the geometric signature, a set of measures that describes topographic form well enough to distinguish among geomorphically disparate landscapes. Different surficial processes create topography with diagnostic forms that...
Authors
R.J. Pike
Preliminary geomagnetic data, College Observatory, Fairbanks, Alaska, June 1988 Preliminary geomagnetic data, College Observatory, Fairbanks, Alaska, June 1988
No abstract available.
Authors
John B. Townshend, R. V. O’Connell, L.Y. Torrence
Preliminary geomagnetic data, College Observatory, Fairbanks, Alaska, September 1988 Preliminary geomagnetic data, College Observatory, Fairbanks, Alaska, September 1988
No abstract available.
Authors
John B. Townshend, R. V. O’Connell, L.Y. Torrence
Preliminary geomagnetic data, College Observatory, Fairbanks, Alaska, October 1988 Preliminary geomagnetic data, College Observatory, Fairbanks, Alaska, October 1988
No abstract available.
Authors
John B. Townshend, R. V. O’Connell, L.Y. Torrence