Publications
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Sedimentary deposits in the northern lowland plains, Mars
The lowland plains on Mars have surfaces marked by large polygonal fracture patterns. It was recently proposed that the fracture patterns were developed on sedimentary deposits from outflow channels. We support this hypothesis because of the following observations. (1) Polygonal fracture patterns tend to occur in low areas on Mars that apparently received influx of sediments; the area of northern
Authors
Baerbel K. Lucchitta, H.M. Ferguson, C.H. Summers
Crustal structure of Yunnan Province, People's Republic of China, from seismic refraction profiles
Seismic refraction, profiles in Yunnan Province, southwestern China, define the crustal structure in an area of active tectonics on the southern end of the Himalaya-Burma arc. The crustal thickness ranges from 38 to 46 kilometers, and the relatively low mean crustal velocity indicates a crustal composition compatible with normal continental crust and consisting mainly of meta-sedimentary and silic
Authors
Rong-Ju Kan, Hong-Xiang Hu, Rong-Sheng Zeng, Walter D. Mooney, T. McEvilly
Influence of welded boundaries in anelastic media on energy flow, and characteristics of P, S-I, and S-II waves: Observational evidence for inhomogeneous body waves in low-loss solids
A general computer code, developed to calculate anelastic reflection-refraction coefficients, energy flow, and the physical characteristics for general P, S-I, and S-II waves, quantitatively describes physical characteristics for wave fields in anelastic media that do not exist in elastic media. Consideration of wave fields incident on boundaries between anelastic media shows that scattered wave f
Authors
Roger D. Borcherdt, Gary Glassmoyer, Leif Wennerberg
Short-period strain (0.1–105 s): Near-source strain field for an earthquake (ML 3.2) near San Juan Bautista, California
Measurements of dilational earth strain in the frequency band 25–10−5 Hz have been made on a deep borehole strainmeter installed near the San Andreas fault. These data are used to determine seismic radiation fields during nuclear explosions, teleseisms, local earthquakes, and ground noise during seismically quiet times. Strains of less than 10−10 on these instruments can be clearly resolved at sho
Authors
M.J.S. Johnston, Roger D. Borcherdt, A. T. Linde
Implications of recent advances in instrumentation for strong-motion studies
No abstract available.
Authors
Roger D. Borcherdt
Crustal structure of Oaxaca, Mexico, from seismic refraction measurements
Seismic refraction and gravity data have been analyzed to obtain a model of the compressional-wave velocity structure of the ocean-to-continent transition in the State of Oaxaca in southwestern Mexico. Crustal thickness on the continent at the latitude 18°N is 45 ± 4 km, based on reflected phases from the Moho discontinuity. The crust has been modeled with three layers, with velocities of 4.3 to 4
Authors
C.M. Valdes, Walter D. Mooney, S.K. Singh, C. Lomnitz, James H. Luetgert, C.E. Helsley, B.T.R. Lewis, M. Mena
Volcano monitoring at the U.S. Geological Survey's Hawaiian Volcano Observatory
The island of Hawaii has one of the youngest landscapes on Earth, formed by frequent addition of new lava to its surface. Because Hawaiian are generally nonexplosive and easily accessible, the island has long attracted geologists interested in studying the extraordinary power of volcanic eruptions. The U.S. Geological Survey's Hawaiian Volcano Observatory (HVO), now nearing its 75th anniversary.
Authors
Christina C. Heliker, J. D. Griggs, T. Jane Takahashi, Thomas L. Wright
Multispectral digital image mapping of Antarctic ice features
Landsat multispectral images of the Antarctic ice sheet have been digitally enhanced by the US Geological Survey to show ice surface features not seen in earlier photographic products of the same scenes. Now for the first time it is worthwhile to prepare image maps at scales of up to 1:250 000 of ice sheet areas even where no nunataks are visible. Derivatives of the data can be stretched to bring
Authors
Charles Swithinbank, Baerbel K. Lucchitta
Book review of Slope Instability, D. Brunsden and D.B. Prior, eds., Wiley, New York, 620 p.
No abstract available.
Authors
Richard M. Iverson
Not-so-inactive fault in Oklahoma
No abstract available.
Prototype operational earthquake prediction system
No abstract available.