An Algorithm for Concurrent Location of Earthquake Epi- and Hypocentres Using P-Arrivals in an Interpolative Tabular Scan

This paper describes an algorithm which can be used to simultaneously locate the Epicentre and Hypocentre of a given Earthquake in a single pass. The data used is a set of P-wave arrival timings, emanating from the given Earthquake. The algorithm uses tables of arrival times formed from a variety of point-to-point (P2P) Ray Tracers, on which it performs a 2-space interpolative scan. The 2-space concerned is Depth and Latitudinal Distance. In this paper there is a full description of the algorithmic process and an example is given of its use. The algorithm appears to be rapid and can routinely locate Epi- and Hypocentre pairs in scanning, say, 1000 points from a specified depth, within 4 seconds on a 3.2 Giga Hertz machine. This is without invoking parallelism and is using data from 10 -12 stations. As such it would seem suitable for use within an Earthquake Early Warning (EEW) regime.