relocation

The length of the interval between the first P- and S-waves is routinely used as a rough estimator of epicentral distance. We propose an algorithm for the relocation of earthquakes occurring in clusters, based on the simultaneous comparison of a large number of intervals. Variations in the intervals at each station are measured by cross-correlation between the respective portions of records directly and without a reference to any absolute times.

Relative locations of the two groups of 2005–2006 Mukacheve series of recurrent earth­quakes were determined using an algorithm designed based on an assumption that a grade of cross-correlation between the records of recurrent events at the same station decays exponentially with separation between their sources, the locations turning out to arrange into almost a flat surface in each of the groups.

Three groups of recurrent earthquakes have been identified within the Mukacheve series of 2005–2006. After relocation with application of differential arrivals and station terms their sources arranged into almost a vertical plane along the azimuth of ~120°, approximately coinciding with a plane of normal faulting determined for all the earthquakes as a single source mechanism.

stable tendency of converging, from different sets of randomly seeded initial locations, to virtually indistinguishable final sets of locations, within each of the groups.