The quake struck off the southern coast of the U.S. territory in the Caribbean Sea at a shallow depth of 6 kilometers, or under 4 miles. The epicenter was recorded just 8 miles south of Indios, Puerto Rico, according to the U.S. Geological Survey. (MORE: Already bracing for tropical depression, Puerto Rico rocked by 6.0 earthquake)
https://abcnews.go.com/US/58-magnitude-earthquake-rocks-puerto-rico/story?id=68092398

