Results of study of anomaly behavior of amplitudes, phase velocities and gradients of ULF electromagnetic disturbances (F = 0.002 – 0.5 Hz) before and during a seismic active period are presented. Investigations were carried out in Japan (Izu and Chiba peninsulas) by two groups of magnetic stations spaced apart at a distance ∼140 km. Every group (magnetic gradientometer) consists of three 3comp...

Repeated cross-correlations of ambient seismic noise indicate a long-term seismic velocity change associated with the 2006 M7.5 slow-slip event (SSE) in the Guerrero region, Mexico. Because the SSE does not radiate seismic waves, the measured velocity change cannot be associated with the response of superficial soil layers to strong shaking as observed for regular earthquakes. The perturbation ...

We demonstrate that an estimate of the point-to-point seismic propagation Green Functions can be extracted from microseisms. These estimated Green’s function, obtained from 30 days of continuous seismic data from 151 seismic stations in Southern California, are used to extract the group velocity of surface waves between all station pairs in the network. The seismic data were then used in a simp...

the mixture of natural and artificial seismic sources with random distributions cause diffuse wave field with random amplitudes and phases called noise. when noise is analyzed in a long-term process, it contains surface waves which are spread in all directions. thus, ambient noise contains data relevant to the surface waves. in recent years, as broadband seismic networks have been distributed v...

Information about reservoir properties usually comes from two sources: seismic data and well logs. The former provide an indirect, low resolution image of rock velocity and density. The latter provide direct, high resolution (but laterally sparse) sampling of these and other rock parameters. An important problem in reservoir characterization is how best to combine these data sets, allowing the ...

Low seismic velocity regions in the mantle and crust are commonly attributed to the presence of silicate melts. Determining melt volume and geometric distribution is fundamental to understanding planetary dynamics. We present a new model for seismic velocity reductions that accounts for the anomalous compressibility of silicate melt, rendering compressional wave velocities more sensitive to mel...

We collected SH-wave seismic reflection data over a shallow aquifer in southwestern British Columbia to investigate the use of such data in hydrogeologic applications. We used this data set in developing a methodology that uses cone penetrometer data as an integral part of the inversion and interpretation of the seismic data. A Bayesian inversion technique converts the seismic amplitude variati...

this paper is devoted to compiling a site geology map for town of amiriyeh, from seismic macro-zonation point of view using geophysical methods of shallow seismic, down-hole seismic and resistivity surveys. in this map site geology has been classified based on shear wave velocity, according to the criteria for site geology classification offered in the iranian code of practice for seismic resis...

We apply seismic interferometry to traffic noise to retrieve both body waves and surface waves. Our preferred algorithm in the presence of highly variable and strong additive random noise uses cross-coherence, which uses normalization by the spectral amplitude of each of the traces, rather than cross-correlation or deconvolution. This normalization suppresses the influence of additive noise and...