Consistent seismic event location and subsurface parameters inversion through slope tomography: a variable-projection approach

International audienceWe revisit the hypocentre-velocity problem, which is of interest in different fields as for example microseismics and seismology. We develop a formulation based on kinematic migration of two picked kinematic attributes in the two dimensional case, the traveltime and the slope (horizontal component of the slowness vector), from which we are able to retrieve the location and subsequently the origin time correction and the subsurface parameters mainly velocity. We show how, through a variable projection, the optimization problem boils down to a physically consistent and parsimonious form where the location estimation is projected into the subsurface parameter problem. We present in this study a proof of concept validated by a toy test in two dimensions and a synthetic case study on the Marmousi model. The method presented in this study is extendible to three dimensions by incorporating the crossline slope or the backazimuth as a supplementary attribute