Robust and reliable techniques for epicenter location using time and slowness observations

Abstract The ever-increasing flow of parameterized and waveform data into various kinds of seismological centers cannot be managed properly unless preliminary epicenter locations are available. Here we demonstrate robust and flexible techniques for fast and reliable event location using the P slowness vector, which is easily derived from arrival times and/or waveform data from arrays, networks, and/or single-site three-component stations. Location schemes are tied to 1) azimuth minimization and 2) slowness vector summation on a sphere using slowness from N arbitrarily positioned stations. The advantage of using azimuth alone is that no assumption is needed of phase type, distance range, or structure (travel-time tables). The viability of our location techniques are demonstrated using a variety of P recordings from networks and three-component stations.