Two earthquakes greater than 5.0 have rocked the Caribbean in the last week and concerns have been growing for a major tremor in the region.
On Tuesday, Feb. 18, a strong 6.5-magnitude quake occurred about 100 miles north-northeast of Bridgetown, Barbados. According to Dr. Joan Latchman, the Director of the Seismic Research Unit of the University of the West Indies, it was the strongest tremor since 1980 in the area.
Three days later, on Feb. 21, a 5.1-magnitude seismic event occurred near Aruba. While both of these quakes did not cause much damage, they are a reminder that the Caribbean remains a very active seismic zone, prone to earthquakes at anytime.
Earthquakes are common in the Caribbean, but most are less than 3.0 on the Richter Scale. The two recent, stronger rumbles have rekindled memories of highly destructive earthquakes over the past few hundred years.
The Caribbean has a long history of destructive tremors.
One of the most infamous occurred in 1692 when a 7.5-magnitude quake dismantled the city of Port Royal, Jamaica. Much of the city was submerged under water, and thousands of people lost their lives.
The Caribbean Plate is sandwiched between numerous tectonic plates including the North American and South American. It is the North American that helps form the Puerto Rico Trench, with depths over 28,000 feet, north of the U.S. territory.
This zone of subduction, where one tectonic plate slowly slide below another, is a concern to many geophysicists.
While destructive quakes, such as the highly destructive Haiti tremor of 2010, have occurred recently, there has not been a major earthquake associated with the Puerto Rico Trench in over 200 years. The last event was a 8.1 tremor in 1787.
According to Woods Hole Oceanographic Institution, based in Massachusetts, there have been a dozen earthquakes in the region over the past 500 years. The institution also notes that tsunamis are a concern and three quakes have been accompanied by a tsunami in Puerto Rico since 1867, the last being in 1946.
With an influx of people to many islands of the Caribbean over the last few decades, much more infrastructure exists across the islands than was around throughout much of the 20th century. A major tremor and potential accompanying tsunami could cause utter destruction to populated areas and create serious economic hardship.
Although the earthquakes of the past week are significant, it is impossible to know if they represent an emerging pattern or if they suggest an upcoming major seismic event.
According to the USGS, the 1787 quake near Puerto Rico caused widespread destruction, including in San Juan. A similar tremor today would no doubt affect hundreds of thousands of people.