Array-based earthquake location for regional earthquake early warning: Case studies from the dead sea transform

Constraining earthquake locations with as few stations as possible is crucial for earthquake early warning. In this study, a new real-time array-based location algorithm is introduced that consists of two modules. The first is a single standalone array module that monitors waveform slowness and back azimuth in a continuous manner and identifies P-and S-phase arrivals. The second is a multiarray module that intersects multiple back-azimuth estimates and surfaces of equal differential arrivals of the P phase. Initial location estimates are issued either by the standalone module, after the S-phase arrival to the first array, or by the multiple arrays module after the P phase arrives to a second array. Location estimates are subsequently updated with data made available by additional arrays. This approach is validated with 10 earthquakes recorded by small-aperture arrays deployed along the Dead Sea Transform. Use of real-time array methodology is particularly suited to environments with sparse network and/or unfavorable source–station configurations.