The island of Puerto Rico was rocked this morning by a 5.8-magnitude earthquake, one of the strongest ones to hit the U.S. territory.

The island had been experiencing small foreshocks during the week, officials said. 

No casualties have yet been reported, though some homes have reportedly cracked and there are power outages. Large boulders were shown to block roads along the southern coast.

The quakes was centered about 10 miles off the south coast. 

According to the Associated Press, shallow quakes had occurring since Dec. 28 along three faults in Puerto Rico’s southwest region: Lajas Valley, Montalva Point and the Guayanilla Canyon.