[1] We simultaneously invert for the velocity and attenuation structure of the North American mantle from a mixed data set: SH wave traveltime and amplitude anomalies, SS wave differential traveltime anomalies, and Love wave fundamental mode phase delays. All data are measured for multiple frequency bands, and finite frequency sensitivity kernels are used to explain the observations. In the res...

The ability to calculate traveltimes and amplitutdes of seismic waves is useful for many reflection seismology applications such as migration and tomography. Traditionally, ray tracing (cerveny et al., 1977; Julian, 1977), paraxial methods (Claerbout, 1971), or full-wave methods (Alterman and Karal, 1968) are used for such calculations. These methods have in common considerable computational ex...

The Stolt migration extension to a varying velocity case (Stolt stretch) implies describing a vertical heterogeneity by a constant parameter (W ). This paper exploits the connection between modified dispersion relations and traveltime approximations to derive an explicit expression for W . The expression provides theoretically the highest possible accuracy within the Stolt stretch framework. Ap...

Based on minimizing a piecewise differentiable lp function subject to a single inequality constraint, this paper discusses algorithms for a discretized regularization problem for ill-posed inverse problems. We examine computational challenges of solving this regularization problem. Possible minimization algorithms such as the steepest descent method, iteratively weighted least squares (IRLS) me...

introduction: nowadays,  considerable developments  in  the field  of  radiotherapy have  been  achieved.  they  include  the  advances  made  in  the  equipments  and  treatment  planning  techniques  which  require  highly complex calculations. such achievements have made it possible to treat cancer patients not only  with  higher  radiation  dose  but  also  with  higher  precision  and  con...