1. A method for determination of a travel time of a seismic wave from a surface location to at least one computation point (CP) within a plurality of subsurface location points comprising: (a) defining a velocity model of a region including said plurality of subsurface location points; (b) computing a monochromatic wavefield, using the velocity model, for the at least one CP; (c) determining an unwrapped phase of the seismic wave at at least one neighboring computation point (NCP) proximate to the at least one CP in said plurality of location points; and (d) determining the travel time of the seismic wave to the at least one CP from said determined unwrapped phase and said computed monochromatic wavefield for the at least one CP.