• Event Date : 01-07-2020
  • Location: Ponce, Puerto Rico
  • Report Date : 06-26-2020
  • Event Category: Earthquake
  • EQ Magnitude: 6.4
  • Report Number: GEER-066
  • DOI: doi:10.18118/G66Q2F
  • Event Latitude: 17.9578
  • Event Longitude: -66.8113
  • Team: Alesandra  C. Morales-Velez
    Miguel  Pando
  • Team Leader First Name: Alesandra
  • Team Leader Last Name: C. Morales-Velez
  • Collaborators: Luis. E Suarez
  • Contributors: Juan Bernal, K. Stephen Hughes, Jan C. Perez, Luis A. Rodriguez
  • Summary: A seismic sequence located along the southwestern coast of Puerto Rico began on 28-December-2019 with a M 4.7 event. This foreshock was followed by an event of M 5.0 on the following day. On 6- January2020 there was a M 5.8 event and then events of M 6.4 and M 5.6 on 7-January-2020 (Lopez et al., 2020a). The seismic sequence has included thousands of events with hundreds of these being felt by residents. Table 1 lists all events larger than M 4.5 from 28-December-2019 until 15-May-2020. The M 6.4 earthquake on 7-January-2020 is considered the “mainshock” for the sequence and triggered the most shaking throughout the southwestern region of Puerto Rico. Although the sequence began in 2019, we refer to it as the “2020” earthquake sequence because most of the events occurred after the new calendar year. Because there are a host of moderate to stronger earthquakes, with one definable main shock, the events together represent a sequence, rather than a swarm.
The work of the GEER Association, in general, is based upon work supported in part by the National Science Foundation through the Geotechnical Engineering Program under Grant No. CMMI-1826118. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the NSF. The GEER Association is made possible by the vision and support of the NSF Geotechnical Engineering Program Directors: Dr. Richard Fragaszy and the late Dr. Cliff Astill. GEER members also donate their time, talent, and resources to collect time-sensitive field observations of the effects of extreme events.