639 research outputs found
Proposed satellite laser ranging and very long baseline interferometry sites for crustal dynamics investigations
Recommendations are presented for a global network of 125 sites for geodetic measurements by satellite laser ranging and very long baseline interferometry. The sites were proposed on the basis of existing facilities and scientific value for investigation of crustal dynamics as related to earthquake hazards. Tectonic problems are discussed for North America peripheral regions and for the world. The sites are presented in tables and maps, with bibliographic references
On the geodetic stability of the Goddard Optical Research Facility
Seismic observations of earthquakes and blasts, geologic analysis of Landsat images, and a search of the historical record was examined. However, no evidence for tectonic motion was found. Some faulting is present in the area but no evidence of seismic activity was found. No elastic resonances in the range from 0.3 to 15 Hz were found. It is concluded that, except for ground water induced changes, the facility is stable at least to the 0.5 cm level
Electric-field-induced displacement of a charged spherical colloid embedded in an elastic Brinkman medium
When an electric field is applied to an electrolyte-saturated polymer gel
embedded with charged colloidal particles, the force that must be exerted by
the hydrogel on each particle reflects a delicate balance of electrical,
hydrodynamic and elastic stresses. This paper examines the displacement of a
single charged spherical inclusion embedded in an uncharged hydrogel. We
present numerically exact solutions of coupled electrokinetic transport and
elastic-deformation equations, where the gel is treated as an incompressible,
elastic Brinkman medium. This model problem demonstrates how the displacement
depends on the particle size and charge, the electrolyte ionic strength, and
Young's modulus of the polymer skeleton. The numerics are verified, in part,
with an analytical (boundary-layer) theory valid when the Debye length is much
smaller than the particle radius. Further, we identify a close connection
between the displacement when a colloid is immobilized in a gel and its
velocity when dispersed in a Newtonian electrolyte. Finally, we describe an
experiment where nanometer-scale displacements might be accurately measured
using back-focal-plane interferometry. The purpose of such an experiment is to
probe physicochemical and rheological characteristics of hydrogel composites,
possibly during gelation
The infrared interferometer spectrometer experiment for the Mars Mariner 1971 orbital mission
Infrared interferometer spectrometer for Mariner spacecraft in Mars orbi
A Geophysical Atlas for Interpretation of Satellite-derived Data
A compilation of maps of global geophysical and geological data plotted on a common scale and projection is presented. The maps include satellite gravity, magnetic, seismic, volcanic, tectonic activity, and mantle velocity anomaly data. The Bibliographic references for all maps are included
Tectonic motion site survey of the National Radio Astronomy Observatory, Green Bank, West Virginia
A geological and geophysical site survey was made of the area around the National Radio Astronomy Observatory (NRAO) to determine whether there are at present local tectonic movements that could introduce significant errors to Very Long Baseline Interferometry (VLBI) geodetic measurements. The site survey consisted of a literature search, photogeologic mapping with Landsat and Skylab photographs, a field reconnaissance, and installation of a seismometer at the NRAO. It is concluded that local tectonic movement will not contribute significantly to VLBI errors. It is recommended that similar site surveys be made of all locations used for VLBI or laser ranging
Methods for thermochemical convection in Earth's mantle with force‐balanced plates
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94785/1/ggge1131.pd
Deep storage of oceanic crust in a vigorously convecting mantle
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94626/1/jgrb15203.pd
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