A new method for high-resolution event relocation and application to the aftershocks of Lushan Earthquake, China

We develop a new method (named hypoRelocate) to determine high-resolution earthquake location, utilizing traditional constraints of absolute travel time and differential travel time, and one new constraint of coda cross-correlogram between the events. The relocation is performed by using a simulated annealing method to search for the best fitting locations and origin times of the events that minimize the total residual of the all above three constraints of the events. HypoRelocate expands the advantage of using differential constraints to better determine high-resolution relative locations between the events by constructing constraint of coda cross-correlograms on interevent distance and reduces the dependence of relocation results on the accuracy of the initial catalog by incorporating the absolute time into the joint inversion. The method is applied to relocate the aftershocks of Lushan Earthquake. The comparisons of the relocation results between hypoRelocate and hypoDD indicate that the additional constraints of coda cross-correlogram and absolute travel time place better constraints on relative location between the events and absolute location of the events.