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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 91 records · Page 5
All sourcesNASA NTRSDOE OSTI
NASA NTRS1965

The nasa geodetic satellite program.

NASA geodetic satellite program, including Earth gravitational field determination, geometric surveying and triangulation net improvement

GEODETIC SURVEYING↗
NASA NTRS1994

The Southern California Dense GPS Geodetic Array

The Southern California Earthquake Center is coordinating a effort by scientists at the Jet Propulsion Laboratory, the U.S. Geological Survey, and various academic institutions to establish a dense 250 station, continuously recording GPS geodetic array in southern California for measuring crustal deformation associated with slip on the numerous faults that underlie the major metropolitan areas of southern california.

geodetic array faults crustal deformation slip rat↗
NASA NTRS2004

Statistical analysis of geodetic networks for detecting regional events

We present an application of hidden Markov models (HMMs) to analysis of geodetic time series in Southern California. Our model fitting method uses a regularized version of the deterministic annealing expectation-maximization algorithm to ensure that model solutions are both robust and of high quality.

geodetic networks↗
DOE OSTI2018

Interseismic Ground Deformation and Fault Slip Rates in the Greater San Francisco Bay Area From Two Decades of Space Geodetic Data

The detailed spatial variations of strain accumulation and creep on major faults in the northern San Francisco Bay Area (North Bay), which are important for seismic potential and evaluation of natural hazards, remain poorly understood. We combine interferometric synthetic aperture radar data from the ERS-1/2 and Envisat satellites between 1992 and 2010 with continuous and campaign GPS data to obtain a high spatial and temporal coverage of ground deformation of the North Bay. The SAR data from both ascending and descending orbits are combined to separate horizontal and vertical components of the deformation. We jointly invert the horizontal component of the mean velocities derived from these data to infer the deep strike-slip rates on major locked faults. We use the estimated deep rates to simulate the long-wavelength deformation due to interseismic elastic strain accumulation along these locked faults. After removing the long-wavelength signal from the InSAR horizontal mean velocity field, we estimate fault-parallel surface creep rates of up to 2 mm/year along the central section of the Rodgers Creek fault and surface creep rates ranging between 2 and 4 mm/year along the Concord fault. No surface creep is geodetically resolved along the West Napa and Green Valley fault zones. We identified characteristically repeating earthquakes on the Rodgers Creek fault, the West Napa fault, the Green Valley fault, and the Concord fault. Finally, nontectonic deformation in the Geysers geothermal field and in Late Cenozoic basins (Rohnert Park and Sonoma basins) are also observed, likely due to hydrological and sediment-compaction processes, respectively.

58 GEOSCIENCES↗