Formulas described in this paper were designed for the use in least-squares tomographic inversion methods with improved flexibility of parametrizing the density-velocity model. The gravity effect of the considered volume fl is the sum of gravity effects of 2-3 or 2 1/2-D bodies of polygonal cross-sections which form the disjunctive decomposition of fi. For this geometrical arrangement analytica...

We have developed a case study of crosshole seismic tomography with a cross-firing geometry in which seismic sources were placed in two vertical boreholes alternatingly and receiver arrays were placed in another vertical borehole. There are two crosshole seismic data sets in a conventional sense. These two data sets are used jointly in seismic tomography. Because the local sediment is dominated...

We formulated an approach to estimate parameters of a layered earth model such as interval velocity, reflector depth, and dip by inverting reflected traveltime with constraints on dipping directions and depth to reflectors. We applied the “shooting method” (Lines, Bourgeois and Covey, 1984) to calculate modeled reflection time. We derived an explicit expression of the Jacobian matrix. The effic...

The efficient computation of finite-frequency traveltime and amplitude sensitivity kernels for velocity and attenuation perturbations in global seismic tomography poses problems both of numerical precision and of validity of the paraxial approximation used. We investigate these aspects, using a local model parameterization in the form of a tetrahedral grid with linear interpolation in between g...

We adopt a recent work in Chung, Qian, Uhlmann and Zhao (Inverse Problems, 23(2007) 309-329) to develop a phase space method for reconstructing pressure wave speed and shear wave speed of an elastic medium from travel time measurements. The method is based on the so-called Stefanov-Uhlmann identity which links two Riemannian metrics with their travel time information. We design a numerical algo...

A higher-order parabolic equation is used to compute the traveltime (phase) and the amplitude in constant density acoustic media. This approach is in the frequency domain, thereby avoiding the high frequency approximation inherent in the Eikonal equation. Intrinsic attenuation can be naturally incorporated into the calculation. The error at large angles of propagation caused by the expansion of...

seismic tomography is an imaging technique which creates maps of subsurface elastic properties such as p/s wave velocity, density and attenuation, based on observed seismograms and use of sophisticated inversion algorithms. amongst different acquisition geometries, seismic cross-hole tomography has a special position in geophysical surveys with many applications in hydrocarbons, coal and other ...

Pseudo-depth monotonicity condition is an important assumption of the inverse scattering internal multiple attenuation algorithm. Analysis reveals that this condition is equivalent to a vertical-time monotonicity condition which is different than the total traveltime monotonicity suggested in recent literature/discussions. For certain complex media, the monotonicity condition can be too restric...