A magnitude 6.0 earthquake struck near Puerto Rico Monday evening, scaring and rousing many from their sleep in the U.S. territory. The U.S. Geological Survey said the quake hit 49 miles off the island's northwest coast at a shallow depth of 6 miles.

Three aftershocks, with magnitudes of 4.7, 4.6 and another of 4.6, hit within less than an hour in the same region at the same depth.

Kiara Hernández, spokeswoman for the island's Emergency Management Agency, told The Associated Press there were no immediate reports of damage and that there was no risk of tsunami. She said emergency management officials were already on alert for the approaching Tropical Depression Karen and communicated quickly with mayors and others across the island to check on any damage. Karen strengthened back into a tropical storm early Tuesday, the National Hurricane Center said, and it caused about 29,000 customers to lose power.

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Its maximum sustained winds increased to 40 mph, with additional strengthening expected. The storm was centered about 35 miles southeast of San Juan and was moving north at about 8 mph. It could bring 3 to 6 inches of rain with isolated amounts of 10 inches.

Hernández said crews would be inspecting buildings to ensure their safety.

San Juan Mayor Carmen Yulín Cruz also said there was no immediate word of damage.

The National Guard also had been activated for the storm, and schools and government offices remained closed as heavy rains were forecast for Puerto Rico on Tuesday, with warnings of possible flooding and landslides.

CBS News correspondent David Begnaud retweeted video of a water main break that apparently followed the temblor:

Earthquake damage: Water main break in Mayagüez which is on the western side of Puerto Rico. https://t.co/SuzBEY3oLD — David Begnaud (@DavidBegnaud) September 24, 2019

Residents react to earthquake

Yahaida Zabala, a 46-year-old San Juan resident, was asleep when she felt her building sway Monday around 11:23 p.m.

"I rushed into my son's room," she said. "He was sitting like he was paralyzed."

They ran down the stairs of their building and stood outside with a small group of people awaiting aftershocks.

The quake was felt across Puerto Rico and was the strongest to hit the island in recent years. While Puerto Rico experiences very small earthquakes on a daily basis that no one feels, seismologists have said it's rare for bigger ones to strike the island.

The last powerful quake to strike Puerto Rico was in January 2014, when a 6.4 magnitude tremor hit after midnight just north of the island's north coast at a depth of 17 miles. Authorities reported broken windows, a busted water line and cracked floors and walls, along with some power outages. Some 70 aftershocks were reported, with at least three of a magnitude 3.5 or greater.

The most damaging earthquake to hit Puerto Rico in recent history occurred in October 1918, a 7.3 magnitude quake that struck near the island's northwest coast, causing a tsunami and killing 116 people.