Quantifying uncertainties on the solution model of seismic tomography

Abstract

Reflection tomography allows the determination of a propagation velocity model that fits the traveltime data associated with reflections of seismic waves in the subsurface. A least-squares formulation is used to compare the observed traveltimes and the traveltimes computed by the forward operator based on a ray tracing. The solution of this inverse problem is only one among many possible models. A linearized a posteriori analysis is then crucial to quantify the range of admissible models we can obtain from these data and the a priori information. The contribution of this paper is to propose a formalism which allows us to compute uncertainties on relevant geological quantities for a reduced computational time. Nevertheless, this approach is only valid in the vicinity of the solution model (linearized framework), complex cases may thus require a nonlinear approach. Application on a 2D real data set illustrates the linearized approach to quantify uncertainties on the solution of seismic tomography. Finally, the limitations of this approach are discussed.