Publications
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Geodetic estimate of coseismic slip during the 1989 Loma Prieta, California, Earthquake
Offsets in the relative positions of geodetic stations resulting from the Loma Prieta earthquake can be explained with a dislocation model that includes buried oblique slip on a rupture surface extending 37 km along the strike of the San Andreas fault, dipping 70° to the SW, and extending from a depth of about 5 to 17.5 km. Assuming uniform slip on a rectangular surface, the mean values for a rang
Authors
Michael Lisowski, W. H. Prescott, James C. Savage, M. J. Johnson
A possible geodetic anomaly observed prior to the Loma Prieta, California, Earthquake
Monthly measurements since mid‐1981 of distance from a geodetic station located 11 km from the epicenter of the Loma Prieta earthquake (Ms = 7.1; October 17, 1989) to three stations 30 to 40 km distant provides an unusually complete record of deformation in the epicentral region in the years prior to an earthquake. Roughly 1.3 years before the earthquake, at about the time of the first magnitude‐5
Authors
Michael Lisowski, W. H. Prescott, James C. Savage, Jerry L. Svarc
An apparent shear zone trending north‐northwest across the Mojave Desert into Owens Valley, eastern California
Strain rates measured at four geodetic networks in eastern California situated between northern Owens Valley and the Transverse Ranges along a small circle drawn about the Pacific‐North America pole of rotation are remarkably consistent. Each exhibits 0.14 μrad/yr simple right‐lateral engineering‐shear‐strain accumulation across the local vertical plane tangent to the small circle. Local faults (e
Authors
James C. Savage, Michael Lisowski, W. H. Prescott
Landslides caused by the intense precipitation of Hurricane Hugo in El Yunque and surrounding areas
No abstract available.
Authors
Matthew C. Larsen
Subsurface energy storage and transport for solar-powered geysers on Triton
The location of active geyser-like eruptions and related features close to the current subsolar latitude on Triton suggests a solar energy source for these phenomena. Solidstate greenhouse calculations have shown that sunlight can generate substantially elevated subsurface temperatures. A variety of models for the storage of solar energy in a sub-greenhouse layer and for the supply of gas and ener
Authors
Randolph L. Kirk, Robert H. Brown, Laurence A. Soderblom
Energy sources for triton's geyser-like plumes
Four geyser-like plumes were discovered near Triton's south pole in areas now in permanent sunlight. Because Triton's southern hemisphere is nearing a maximum summer solstice, insolation as a driver or a trigger for Triton's geyser-like plumes is an attractive hypothesis. Trapping of solar radiation in a translucent, low-conductivity surface layer (in a solid-state greenhouse), which is subsequent
Authors
R. H. Brown, Randolph L. Kirk, T. V. Johnson, Laurence A. Soderblom
Triton's geyser-like plumes: Discovery and basic characterization
At least four active geyser-like eruptions were discovered in Voyager 2 images of Triton, Neptune's large satellite. The two best documented eruptions occur as columns of dark material rising to an altitude of about 8 kilometers where dark clouds of material are left suspended to drift downwind over 100 kilometers. The radii of the rising columns appear to be in the range of several tens of meters
Authors
Laurence A. Soderblom, S. W. Kieffer, T.L. Becker, R. H. Brown, A.F. Cook, C.J. Hansen, T. V. Johnson, Randolph L. Kirk, E.M. Shoemaker
Volcanism in Northwest Ishtar Terra, Venus
Soviet Venera 15/16 radar images and topographic data for an area in NW Ishtar Terra, Venus (74°N, 313°E) contain evidence for the existence of a complex volcanic center. Located at the intersection of Akna and Freyja Montes (both elevated ∼4 to 7 km above the planetary reference radius of 6051 km), this volcanic center has a complex caldera system, possibly more than one major eruptive vent, and
Authors
Lisa R. Gaddis, Ronald Greeley
Dark materials in Valles Marineris: Indications of the style of volcanism and magmatism on Mars
Rifting on the equatorial canyon system of Valles Marineris provides a unique view of the interior of the Martian crust to depths reaching 7 km, exposing several in situ bedrock units which testify to past volcanic and magmatic processes on Mars. A thick, regionally extensive deposit observed in Coprates and Juventae chasmata is interpreted on the basis of spectral reflectance, erosional morpholog
Authors
Paul E. Geissler, Robert B. Singer, Baerbel K. Lucchitta
Landslide processes in saprolitic soils of a tropical rain forest, Puerto Rico
Shallow soil slips, earth and debris slides appear to be a primary mechanism of hillslope denudation in the rainforest of eastern Puerto Rico. Annual rainfall in excess of 4,000 mm, and thick sequences (up to 20 m) of residual soils (saprolite) combine to produce these landslides. Shear strength testing and observatons of tension cracks indicate that landslides may start as tensile failure of sapr
Authors
Matthew C. Larsen, Andrew Simon
Rainfall-soil moisture relations in landslide-prone areas of a tropical rain forest, Puerto Rico
Soil moisture conditions are not well documented in steep, tropical landslide-prone terrain. In the 11,330 ha Caribbean National Forest (CNF) in northeastern Puerto Rico more than 170 landslides that occurred from one to approximately 60 years ago have been mapped. Most of these landslides are shallow, with failure depths of 0.5 ot 7 m, and are associated with periods of intense, prolonged rainfal
Authors
Matthew C. Larsen, Angel J. Torres-Sanchez
Liquefaction and foundation failure of Chevron oil and gasoline tanks at Moss Landing, California
Liquefaction of gray, coarse‐ to medium‐grained, esturine sand during the October 17, 1989 Loma Prieta (Ms=7.1) earthquake led to foundation failures of oil and tanks at the Chevron Marine Station at Moss Landing located about 25 km south‐southeast of the epicenter. Differential settlement of the foundations resulted in 1° to 6° of the tanks towards one another and an associated 2° to 7° inclinati
Authors
Martitia Tuttle, Patience Cowie, John Tinsley, Michael Benett, John Berrill