Within the last 7 days, dozens of earthquakes have rattled Puerto Rico and surrounding areas; despite the seismic activity, there is still no threat of tsunami from the quakes. Of the 94 earthquakes to shake Puerto Rico in the last 7 days, 25 struck within the last 24 hours. Of those last 25, 9 were over a magnitude 2.5 event and could be felt. The three strongest quakes of this swarm in the last 24 hours were a 4.2, 3.6, and 3.7 magnitude earthquake. None of the earthquakes over the last week were strong enough to displace any water to create a tsunami.
The strongest of the series in the last 24 hours struck at a depth of 117 km roughly 13 km north-northeast of Otra Banda on the Dominican Republic. The epicenter was roughly 160 miles west of San Juan, Puerto Rico. While this is the location of the strongest quake of the set, the epicenter isn’t near where most earthquakes have occured in the last week and day.
Most earthquakes are occuring along the southwest coast of Puerto Rico, not far from the epicenter of a strong earthquake that hit in January 2020. That 6.4 created extensive damage in Puerto Rico, including widespread power failures across much of the island. An earthquake swarm started here in December 2019 and unrest has continued since.
These earthquakes are occurring near the northern edge of the Caribbean Plate, a mostly oceanic tectonic plate underlying Central America and the Caribbean Sea off of the north coast of South America. The Caribbean Plate borders the North American Plate, the South American Plate, the Nazca Plate, and the Cocos Plate. The borders of these plates are home to ongoing seismic activity, including frequent earthquakes, occasional tsunamis, and sometimes even volcanic eruptions.
Just last month, officials across the Caribbean held a tsunami and earthquake drill, simulating a strong earthquake and potential tsunami. On March 10, through the CaribeWave ’22 Tsunami Warning System Exercise, officials drilled for a hypothetical situation that could create significant damage and a basin-wide tsunami if it were to occur. Included in that exercise was a magnitude 8.0 earthquake that strikes near the southeastern coast of the Dominican Republic.