Publications
Filter Total Items: 7614
Preliminary geomagnetic data, College Observatory, Fairbanks, Alaska Preliminary geomagnetic data, College Observatory, Fairbanks, Alaska
No abstract available.
Authors
John B. Townshend, R. V. O’Connell, Carol Ann Varner
Preliminary geomagnetic data, College Observatory, Fairbanks, Alaska Preliminary geomagnetic data, College Observatory, Fairbanks, Alaska
No abstract available.
Authors
John B. Townshend, R. V. O’Connell, Carol Ann Varner
Preliminary geomagnetic data, College Observatory, Fairbanks, Alaska Preliminary geomagnetic data, College Observatory, Fairbanks, Alaska
No abstract available.
Authors
John B. Townshend, R. V. O’Connell, Carol Ann Varner
Report on list of structures recommended for seismic instrumentation in the Puget Sound area, Washington Report on list of structures recommended for seismic instrumentation in the Puget Sound area, Washington
No abstract available.
Authors
B. M. Olsen, P. Grant, Mehmet Çelebi
A direct method for calculating instrument noise levels in side-by-side seismometer evaluations A direct method for calculating instrument noise levels in side-by-side seismometer evaluations
The subject of determining the inherent system noise levels present in modem broadband closed loop seismic sensors has been an evolving topic ever since closed loop systems became available. Closed loop systems are unique in that the system noise can not be determined via a blocked mass test as in older conventional open loop seismic sensors. Instead, most investigators have resorted to...
Authors
L. Gary Holcomb
A broad-band, wide-dynamic range, strong-motion array near Parkheld, California, USA for measurement of acceleration and volumetric strain A broad-band, wide-dynamic range, strong-motion array near Parkheld, California, USA for measurement of acceleration and volumetric strain
No abstract available.
Authors
Roger D. Borcherdt, Malcolm J. S. Johnston, Thomas Noce, Gary Glassmoyer, Douglas Myren
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