The objective of this work is to build an efficient algorithm (a) to estimate seismic velocity from time-migration velocity, and (b) to convert time-migrated images to depth. We establish theoretical relations between the time-migration velocity and the seismic velocity in 1 Page 1 of 23 GEOPHYSICS 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 3...

The upper lithospheric structure from the Pilbara Craton, across the Capricorn Orogen, to the northern Yilgarn Craton is determined from high-fidelity broadband seismic data. Three-component temporary stations were deployed in a line running southwards from Marble Bar, Western Australia, at approximately 118 E longitude. They were in position between July and October 2000. Receiver functions ar...

We have developed an inversion formulation for velocity and attenuation structure using seismic attributes, including envelope amplitude, instantaneous frequency and arrival times of selected seismic phases. We refer to this approach as AFT inversion for amplitude, (instantaneous) frequency and time. Complex trace analysis is used to extract the different seismic attributes. The instantaneous f...

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...