Publications

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 to firmly

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 stresses on the

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 on the surf

No abstract available.

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 data sets,

87Sr/86Sr ratios determined for samples from a 350 m core of Neogene lagoonal, shallow-water limestones from Enewetak Atoll display a remarkably informative trend. Like the recently published data for Deep Sea Drilling Project (DSDP) carbonates, 87Sr/86Sr at Enewetak increases monotonically but not smoothly from the early Miocene to the Pleistocene. The data show intervals of little or no change i

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 of quartzi

A catastrophic rainstorm in central California on January 3-5,1982, dropped as much as half the mean annual precipitation within a period of about 32 hours, triggering landslides and floods throughout 10 counties in the vicinity of the San Francisco Bay. More than 18,000 of the slides induced by the storm transformed into debris flows that swept down hillslopes or drainages with little warning. De

No abstract available.

Crustal velocity sections based on two seismic-refraction profiles are presented for the area west of Yucca Mountain, Nye County, Nevada. The Crater Flat profile is interpreted in terms of six velocity layers ranging from 1.5 to 6.1 km/s. Interpretation of the Beatty profile reveals an escarpment near the northeast edge of Bare Mountain, where Paleozoic rocks are probably down-faulted 2600 m into

No abstract available.

We mapped 221 large (more than 200 ft across) landslides of three morphologically distinct types on the bluffs bordering the Mississippi alluvial plain in western Tennessee and Kentucky Old coherent slides (146 landslides, or 66 percent of the total) include translational block slides and single and multiple-block rotational slumps, all of which are covered by mature vegetation and have eroded fea