Map showing earthquakes (circles) with a magnitude greater than or equal to 5 in the Puerto Rico Seismic Network catalog. The color of the circles indicate the time after the initial Dec. 28, 2019 magnitude-4.7 event. The size of the circles corresponds to magnitude. Triangles show the location of permanent Puerto Rico Seismic Network seismic stations (black), pre-existing Puerto Rico Seismic Network stations improved with additional equipment added to monitor the sequence (black and yellow), temporary stations installed by the Puerto Rico Seismic Network (yellow), and temporary stations installed by the USGS (blue). Select focal mechanisms from the Advanced National Seismic System Comprehensive Earthquake Catalog are shown, which includes data from the National Earthquake Information Center.