Publications

Ground-water levels in Lancaster, California, declined more than 200 feet during the 20th century, resulting in reduced ground-water supplies and more than 6 feet of land subsidence. Facing continuing population growth, water managers are seeking solutions to these problems. Injection of imported, treated fresh water into the aquifer system when it is most available and least expensive, for later

Two-dimensional convection models with moving continents show that continents profoundly affect the pattern of mantle convection. If the continents are wider than the wavelength of the convection cells (-3000 km, the thickness of the mantle), they cause neighboring deep mantle thermal upwellings to coalesce into a single focused upwelling. This focused upwelling zone will have a potential temperat

We examine the hypothesis that dynamic deformations associated with seismic waves trigger earthquakes in many tectonic environments. Our analysis focuses on seismicity at close range (within the aftershock zone), complementing published studies of long-range triggering. Our results suggest that dynamic triggering is not confined to remote distances or to geothermal and volcanic regions. Long unila

The 23 October 2002 Nenana Mountain Earthquake (Mw ∼ 6.7) occurred on the Denali Fault (Alaska), to the west of the Mw ∼ 7.9 Denali Earthquake that ruptured the same fault 11 days later. We used 6 interferograms, constructed using radar images from the Canadian Radarsat-1 and European ERS-2 satellites, to determine the coseismic surface deformation and a source model. Data were acquired on ascendi

No abstract available.

No abstract available. 

This report describes seismic data obtained during the fourth Seismic Hazard Investigation of Puget Sound (SHIPS) experiment, termed Seattle SHIPS . The experiment was designed to study the influence of the Seattle sedimentary basin on ground shaking during earthquakes. To accomplish this, we deployed seismometers over the basin to record local earthquakes, quarry blasts, and teleseisms during the

Using P and S arrival times from 4625 local and regional earthquakes recorded at 174 seismic stations and associated geophysical investigations, this paper presents a three‐dimensional crustal and upper mantle velocity structure of southwestern China (21°–34°N, 97°–105°E). Southwestern China lies in the transition zone between the uplifted Tibetan plateau to the west and the Yangtze continental pl

Lithospheric buoyancy, the product of lithospheric density and thickness, is an important physical property that influences both the long-term stability of continents and their state of stress. We have determined lithospheric buoyancy by applying the simple isostatic model of Lachenbruch and Morgan (1990). We determine the crustal portion of lithospheric buoyancy using the USGS global database of

The origin and evolution of cratonic roots has been debated for many years. Precambrian cratons are underlain by cold lithospheric roots that are chemically depleted. Thermal and petrologic data indicate that Archean roots are colder and more chemically depleted than Proterozoic roots. This observation has led to the hypothesis that the degree of depletion in a lithospheric root depends mostly on

[1] We present a new crustal section across northwest China based on a seismic refraction profile and geologic mapping. The 1100‐km‐long section crosses the southern margin of the Chinese Altai Mountains, Junggar Accretional Belt and eastern Junggar basin, easternmost Tianshan Mountains, and easternmost Tarim basin. The crustal velocity structure and Poisson's ratio (σ), which provide a constraint

This report was prepared in response to a written request from the City of Vallejo, California, to the U.S. Geological Survey (USGS). By letter of October 4, 2002, the City requested that the USGS "provide advice to the City’s LNG Health and Safety Committee on its review of a potential liquid natural gas project" on the southern portion of Mare Island. The City specifically requested that the USG