This paper presents a new traveltime inversion method based on the wave equation. In this new method, designated as wave-equation traveltime inversion (WT), seismograms are computed by any full-wave forward modeling method (we use a finitedifference method). The velocity model is perturbed until the traveltimes from the synthetic seismograms are best fitted to the observed traveltimes in a leas...

Seismic imaging, popularly known as tomography, borrowing the term from medical sciences, produces the raster image of the internal structure by combining information from a set of projections obtained at different viewing angles. To engineer high resolution and accurate solutions to mining problems, seismic traveltime tomography can yield a high resolution image of the subsurface to provide in...

In this work an adaptive strategy for the phase space method [5] for traveltime tomography is developed. The method uses those geodesics/rays that produces smaller mismatch with the measurements first and continue on in the spirit of layer stripping without the need to specifically defining the layers physically. The adaptive approach improves stability, efficiency and accuracy. We then extend ...

Fermat's principle shows that a deenite convex set of feasible slowness models { depending only on the traveltime data { exists for the fully nonlinear traveltime inversion problem. In a new iterative reconstruction algorithm, the minimum number of nonfeasible ray paths is used as a gure of merit to determine the optimum size of the model correction at each step. The numerical results show that...

A new 2-D traveltime tomography algorithm has been developed for use with long offset seismic streamer data. The forward problem is solved using initial value ray tracing in Delaunay triangulated grids. The traveltimes are calculated analytically. The linearised joint interface and velocity inversion is regularised via a geostatistical smoothing regularisation based on the formulation of a data...

The rst arrival quasi-P wave traveltime eld in an anisotropic elastic solid solves a rst order nonlinear partial diierential equation, the qP eikonal equation. Since the qP slowness surface is convex, the rst arrival traveltime along downward propagating rays solves the paraxial qP eikonal equation, an evolution equation in depth. A second order upwind nite diierence scheme solves this paraxial...

Nonuniqueness in traveltime tomographic velocity analysis is largely the result of insufficiency in model parameterization. Traditional tomography parameterizes the model with nonoverlapping cells. Such single-scale tomography (SST) from inverting traveltimes only may produce underdeterminacy at places of insufficient ray coverage. To cope with the poor and uneven ray coverage, a multiscale tom...