Results 251 to 260 of about 12,885 (295)

Shear-wave splitting in compliant rocks

open access: yesThe Leading Edge, 2010
Shear-wave splitting is a phenomenon that has received a lot of attention primarily because of its connection with vertically aligned cracks or fractures within reservoirs. However, in most cases the largest amount of shear-wave splitting is observed to occur in the near-surface layers where the rocks are the least consolidated, and so are least likely
Peter Cary   +3 more
openaire   +2 more sources

Splitting parameter yield (SPY): A program for semiautomatic analysis of shear-wave splitting

open access: yesComputers & Geosciences, 2012
SPY is a Matlab algorithm that analyzes seismic waveforms in a semiautomatic way, providing estimates of the two observables of the anisotropy: the shear-wave splitting parameters. We chose to exploit those computational processes that require less intervention by the user, gaining objectivity and reliability as a result.
Lucia Zaccarelli   +2 more
openaire   +2 more sources

Shear-wave splitting measurements — Problems and solutions

Tectonophysics, 2008
Abstract We compare sensitivity and reliability of three basic techniques of shear-wave splitting analysis – cross-correlation of wave components, minimization of covariance matrix eigenvalues and minimizing energy on the transverse component – of both synthetic and real data, point out some problems and propose solutions.
Ludek Vecsey   +2 more
exaly   +2 more sources

Thin layers and shear-wave splitting

Geophysics, 1991
Abstract The near-surface weathering layer is considered by many to be strongly anisotropic. Any shear-wave signal passing through this low-velocity layer will inherit, to some degree, the anisotropic response of this layer. For thin weathering layers, information about previous anisotropic events may be distorted; when the thickness ...
R. D. Slack   +3 more
openaire   +1 more source

SWAS: A shear-wave analysis system for semi-automatic measurement of shear-wave splitting above small earthquakes

open access: yesPhysics of the Earth and Planetary Interiors, 2006
The complexity of shear wave-arrivals above small earthquakes makes the polarisations and time-delays of shear-wave splitting above small earthquakes difficult to measure.
Yuan Gao, Stuart Crampin
exaly   +2 more sources

A New Understanding of Shear-Wave Splitting

Proceedings, 1995
Shear-wave splitting (shear-wave- bi-refringence) diagnostic of some form of azimuthal anisotropy is widely observed in all types of rock in the uppermost 15km of the Earth's crust (Crampin and Lovell 1991).
S. Crampin, S. V. Zatsepin
openaire   +1 more source

Shear Wave Splitting in Himalaya

Chinese Journal of Geophysics, 2007
AbstractWe analyze the records of 56 stations in Himalaya area with the method of minimizing the eigenvalue. Splitting was observed at thirty‐nine stations of them. The average splitting time is about 0.8s. The parameters of splitting vary not only from south to north, but are also different on the two sides of the line joining the station GAIG and ...
openaire   +1 more source

Bootstrapping shear-wave splitting errors

Bulletin of the Seismological Society of America, 1994
Abstract We have developed a bootstrap method to estimate errors associated with inverting SKS waveforms for shear-wave splitting parameters. Although presented for shear-wave splitting inversions, this method is suitable for any waveform inversion procedure.
Eric Sandvol, Thomas Hearn
openaire   +1 more source

Shear-wave splitting near Guam

Physics of the Earth and Planetary Interiors, 1992
Abstract Polarities of shear waves from intermediate-focus events underneath Guam are studied. For records from a group of ten events, shear-wave splitting with faster-arriving E-W components are observed. This event group occurred within, or above, one geographic portion of the Wadati-Benioff zone, with depths ranging between 57 and 148 km.
openaire   +1 more source

Amplitude effects associated with shear‐wave splitting

SEG Technical Program Expanded Abstracts 2009, 2009
Shear-wave anisotropy results in a time delay between two different shear-wave polarizations S1 and S2. If there are associated differences in attenuation of the amplitudes, then simple time shifting is insufficient to match the S1 and S2 images. This ―differential‖ attenuation leads to both an additional time delay and a frequency dependent amplitude ...
Bruno Gratacos   +2 more
openaire   +2 more sources

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