A 6.0-magnitude earthquake struck near Puerto Rico late Monday, rousing and scaring many from their sleep in the U.S. territory.

The U.S. Geological Survey said the quake struck 49 miles (79 kilometers) off the island’s northwest coast at a shallow depth of 6 miles (10 kilometers). Three aftershocks, of magnitude 4.7 and 4.6, hit within less than an hour in the same region at the same depth.

Read more at PBS News.