Puerto Ricans are particularly fond of memes, and they quickly shared one showing the collapsed natural arch covered with a blue tarpaulin like the ones that still cover many homes whose roofs were damaged during Hurricane Maria in 2017.

Among them was Mr. Rodríguez’s house in the Esperanza neighborhood of Guánica, where some of the most serious damage was reported, including five collapsed houses. Now, in addition to the tarp he has had since Maria, Mr. Rodríguez’s house has huge cracks running up and down his green interior walls.

“It cracked open everywhere inside,” said Mr. Rodríguez, 83, a retired bus driver.

The first cracks appeared a few days ago, after the first temblors. They worsened on Monday, and pipes in the bathroom broke, leading to some flooding.

Luz Dastas, 51, whose house in Guánica is also covered by a leaky blue tarp, left with her 26-year-old daughter, Aida Torres, after the first tremors. Monday’s quake opened new cracks in the walls of her house.

When her granddaughter, Alondra Suárez, 7, felt the earth shake one recent night, “I stayed up until the morning,” Alondra said. “I ate a chocolate to see if I could feel better.”

On Monday, strong aftershocks of 4.9, 4.3 and 4.4 magnitude continued to rock the island into the late afternoon, rattling nerves over and over again. Officials warned of possible mudslides and urged people to stay off the roads to allow emergency personnel to assess the damage.