Modeling First Arrivals in Heterogeneous Velocity Grids for Traveltime Tomography

T020 MODELING FIRST ARRIVALS IN HETEROGENEOUS VELOCITY GRIDS FOR TRAVELTIME TOMOGRAPHY Abstract 1 First-arrival traveltimes can provide a valuable information about subsurface velocity structure. Seismic measurements carried out between boreholes allow reconstructing velocity models of the medium between them using tomographic inversion algorithms. The technique uses first-arrival traveltimes to retrieve velocity images by resolving a system of algebric equations. The aim of this paper is to present an efficient algorithm that predicts first arrivals of seismic waves in heterogeneous velocity media for arbitrary locations of sources and receivers. Introduction Traveltime tomography uses picked fastest arrivals to deduce velocity variations in