P332 Traveltime Computations for Locating the Source of Micro Seismic Events and for Forming Gridded Traveltime Maps J.C. Bancroft* (University of Calgary) & X. Du (University of Calgary) SUMMARY A new method is presented for estimating the source location of an event based on the assumption that the event creates a spherical wavefront which is recorded by a number of receivers with fixed locations. This method is suitable for locating microseismic events mapping traveltimes that are computed along raypaths to gridded times or for propagating first arrival times on a grid. Previous methods that computed traveltimes with spherical (or circular)