Results 151 to 160 of about 1,427 (180)

4D seismic coda waves

80th EAGE Conference & Exhibition 2018 Workshop Programme, 2018
Time-lapse seismic imaging of the earth's interior, and quantitative estimation of time-varying changes in rock and fluid properties, has produced many spectacular results over the past 30 years; however, we are still making many approximations, and extracting only a small percentage of the information available in the full time-lapse seismic ...
openaire   +1 more source

Elastic rays and coda wave interferometry.

The Journal of the Acoustical Society of America, 2010
We apply the concept of rays, well known from geometric optics, to elastic waves traveling in a finite solid. Ray splitting and mode conversion between compressional P-waves and transversal S-waves are taken into account by using a random walk procedure and Monte-Carlo integration.
Thomas Gorin, Adrian Ortega
openaire   +1 more source

Attenuation of Coda Waves in Hungary

Acta Geodaetica et Geophysica Hungarica, 2000
Microearthquake codas from 19 shallow depth local events have been analysed in Hungary. We estimate coda attenuation Qc in the frequency range 6 to 24 Hz used Sato’s (1977) single scattering model for a coda window of 12.5±2.5 s beginning at twice the S-wave travel time. Travel times were between 2–23 sec. The stations showed similar values of Qc which
openaire   +1 more source

Phenomenological Modeling of Coda-Wave Excitation

1998
As discussed in Section 2.4.1, the excitation of S-coda waves is one of the most compelling pieces of evidence supporting the existence of random heterogeneity in the lithosphere. Aki and Chouet [1975] summarized the characteristics of highfrequency S-coda waves of local earthquakes, like those shown in Figure 2.21, as follows: (1) the spectral ...
Haruo Sato, Michael C. Fehler
openaire   +1 more source

Analyzing the coda from correlating scattered surface waves

The Journal of the Acoustical Society of America, 2012
The accuracy of scattered Rayleigh waves estimated using an interferometric method is investigated. Summing the cross correlations of the wave fields measured all around the scatterers yields the Green’s function between two excitation points. This accounts for the direct wave and the scattered field (coda). The correlations themselves provide insights
Mikesell, T. Dylan, van Wijk, Kasper, Blum, Thomas E., Snieder, Roel, Sato, Haruo   +4 more
openaire   +4 more sources

Attenuation of coda waves in northern Greece

pure and applied geophysics, 1993
The single scattering model has been applied for the estimation of codaQ values for local earthquakes that occurred in northern Greece during the period 1983–1989 and recorded by the telemetered network of the Geophysical Laboratory of the University of Thessaloniki.
openaire   +1 more source

Coda Wave Analysis to Monitor Processes in Soils

Journal of Geotechnical and Geoenvironmental Engineering, 2013
AbstractSmall-strain elastic wave propagation is a constant-fabric phenomenon ideally suited to monitor processes in soils. However, the determination of very small changes in travel time limits our ability to resolve changes in soil stiffness caused by internal processes or changes in boundary conditions.
Sheng Dai, Frank Wuttke, J. Carlos Santamarina   +2 more
openaire   +1 more source

Coda wave interferometry and the equilibration of energy in elastic media

Physical Review E, 2002
Multiple-scattered waves usually are not useful for creating deterministic images of the interior of elastic media. However, in many applications, one is not so much interested in making a deterministic image as in detecting changes in the medium. Cases in point are volcano monitoring and measuring the change in hydrocarbon reservoirs during enhanced ...
openaire   +2 more sources

Scattered Surface Wave Energy in the Seismic Coda

pure and applied geophysics, 2006
One of the many important contributions that Aki has made to seismology pertains to the origin of coda waves (Aki, 1969; Aki and Chouet, 1975). In this paper, I revisit Aki's original idea of the role of scattered surface waves in the seismic coda.
openaire   +1 more source

Attenuation of coda waves in the Dead Sea region

Bulletin of the Seismological Society of America, 1988
AbstractCoda waves of local small earthquakes in the Dead Sea region, part of the Jordan rift structure, show frequency invariant codas, that is Qc = Q0(f/f0)n, with Q0 = 65 ± 5, f0 = 1 Hz and n = 1.05 ± 0.04 for hypocentral distances between 10 and 55 km, and lapse times less than 60 sec.
openaire   +1 more source