As Lights Flicker On in Puerto Rico, Officials Say 3 More Have Died

The only death directly linked to structural damage occurred in Ponce, where Nelson Martínez, 73, died when an unfinished bathroom wall fell on him while he was in bed.

Since the quake, thousands of people in southern Puerto Rico have been spending nights outside — in hammocks, on inflatable mattresses and in tents. Fearing additional tremors, many Puerto Ricans are too afraid to sleep in their own homes. At least 6,000 more quake survivors are in shelters, said Jenniffer González-Colón, Puerto Rico’s representative in Congress.

“We’re used to hurricanes,” she said. “We’re not used to earthquakes.”

Dozens of tremors have been felt in the days since the pre-dawn quake tumbled houses and schools.

The crisis that has again plunged Puerto Rico into darkness was caused when the island’s power plants shut down automatically after the tremors. Officials discovered that one of the biggest plants was so damaged that it could not be immediately repaired.

By Friday morning, about 20 percent of the Puerto Rico Electric Power Authority’s roughly 1.5 million customers remained without power, the utility said, but it was far from clear when the remaining customers would have electricity again. Gov. Wanda Vázquez said this week that she could not provide a date for when the power would return to all of the island’s residents.

The damaged Costa Sur plant, which produces more power than any other plant on the island, could take a year to repair, Mr. Ortiz said at a news conference on Thursday. Other plants may come back online by Sunday, Mr. Ortiz said, but he warned that the system would remain unstable for several weeks.

“In the coming hours and days, we should have 100 percent power back,” Mr. Ortiz said.

Patricia Mazzei reported from San Juan, P.R., and Frances Robles from Miami. Alejandra Rosa contributed reporting from San Juan and Nicholas Bogel-Burroughs from New York.