Earthquake Swarms in Southern Hispaniola Revealed by Spatiotemporal Evolution of Seismicity from Multi-Station Template Matching

Abstract

ABSTRACT Earthquake swarms have provided useful insights into driving mechanisms for triggered earthquakes. However, a majority of earthquake swarms consist of microseismicity in which observations sometimes are limited because of detection ability. Here, we apply a multi-station template matching technique to two temporary seismic networks and investigate microseismicity in southern Hispaniola. We detect a total of 6065 and 1366 new events for the 2010 and 2013–2014 datasets, respectively, using templates from pre-existing catalogs. The magnitude of completeness (Mc) of our updated catalogs drops from 1.7 to 1.2 and from 2.2 to 1.4 for the 2010 and 2013–2014, respectively, after combining new detections with the templates. With the improvement of seismic detections, the spatiotemporal distribution of the seismicity showcases three instances of earthquake swarms. The first one is located offshore on the Trois Baies fault, with over one thousand events triggered during mid-February to early March 2010, whereas the other one is distributed along the western Léogâne fault, which occurs within a day and shows many earthquakes with similar waveforms. The third one is found in the north of Lake Enriquillo in the Dominican Republic, which outlines a nearly vertical fault plane. Our updated earthquake catalogs and observations of these swarms provide necessary information for seismic hazard assessment in southern Hispaniola and will facilitate continued investigations of seismology in the area.