A 5.2 magnitude aftershock was felt in southern Puerto Rico Friday afternoon, days after two other high magnitude earthquakes left one dead, many injured and caused an island-wide loss of power.

In the days after a 6.4 magnitude earthquake struck on Tuesday, the U.S. Geological Survey (USGS) said aftershocks were likely to occur within the week, and predicted the likelihood would decrease over time. On Friday alone, the island felt nearly 30 aftershocks that were lower than 3.5 magnitude.

USGS reports the 6.4 magnitude earthquake struck that struck Tuesday occurred about five miles south of the city of Indios.

The Federal Communications Commission (FCC) reported Friday that cell towers remain down throughout most of the island, though cell tower outages do not necessarily correspond to the availability of wireless service in that area, according to the agency.

Some parts of the island are more affected than others and service is being restored each day. Eight Puerto Rico counties have between 31-45 towers down as of Friday.

President Donald Trump declared a state of emergency on Wednesday, authorizing the Department of Homeland Security (DHS) and the Federal Emergency Management Agency (FEMA) to coordinate disaster relief efforts. Puerto Rico Governor Wanda Vázquez Garced also declared a state of emergency Tuesday, activating the island’s National Guard.

Thousands of people are now staying in shelters and sleeping on sidewalks, according to the AP, and classes have been closed since Monday’s quake.

The island has experienced over 500 earthquakes since December 28, when a 4.7 magnitude quake struck in the same region, according to the USGS. Thirteen of the earthquakes since then have been higher than 4.0, including the quakes on Monday and Tuesday, the USGS also reported. Tuesday’s quake was the most severe since Dec. 28. At least nine people have been injured in building collapses, according to the AP.

USGS announced Thursday that there’s an 84% chance that aftershocks will continue, but will decrease in frequency for the next 30 days. It is also not likely the island will see a shock with a magnitude as high as Tuesday’s quake.

USGS says there is currently no threat of tsunami — though some municipalities along the southern coast began evacuating out of fear, according to Puerto Rico’s emergency management office.

Carmen Guzmán-Mato tells TIME she and her family fled from the southern town of Parguera, where they had been vacationing, to San Juan on Tuesday morning. “It felt like the house was sinking; we woke up in a panic,” she said.

Officials sounded a tsunami siren Tuesday morning that forced the town’s residents to run and drive uphill. The tsunami warning was a false alarm, but it was enough to push the family into leaving.

“I started vomiting, I believe, out of anxiety,” says Guzmán-Mato, who is from Puerto Rico but is currently living in Brooklyn, New York. Her family stayed in the town until daybreak, then decided to evacuate. “It was tough because you want to leave, you want to get out of there, but at the same time it’s like, well, what if you’re on a road and all of a sudden another [earthquake] happens?”

Earlier USGS reports indicated Tuesday morning’s earthquake was a magnitude 6.6, but the number has since been adjusted to 6.4. Puerto Rico now faces likely aftershocks of magnitude 3 or higher in the coming week, USGS says. The agency has deployed six portable seismometers to the island to help with monitoring, USGS said Tuesday afternoon.

Damage from Monday’s 5.8 magnitude earthquake destroyed several buildings, including one school. Puerto Rico’s electricity supplier, Autoridad de Energía Eléctrica, has reported an island-wide power outage as a result of Tuesday’s 6.4 magnitude earthquake. The company has restored power to 83% of the island as of Friday afternoon.

Here’s what to know about the earthquakes striking Puerto Rico, an island still recovering from 2017’s Hurricane Maria.

Who are the victims?

According to the AP, 73-year-old Nelson Martínez was killed after a wall collapsed on him in his home in Ponce, about 14 miles away from the earthquake’s epicenter. Nine others were injured, according to the AP.

How are authorities and Puerto Ricans responding?

Before declaring a state of emergency, Vázquez Garced announced Tuesday morning that all government employees except for first responders have been relieved from duty for the day in order to prioritize safety. The governor’s office also urged the public to remain calm.

The governor’s office approved $130 million to aid in the emergency, Vázquez Garced announced at a Tuesday morning press conference. The office has also set up a mobile unit in Ponce to coordinate recovery efforts. FEMA has also deployed two incident management teams to the island.

Puerto Rican officials also began the process of assessing damage and identifying further possible casualties. Vázquez Garced urged Puerto Ricans to reach out to family, friends and neighbors, especially the elderly or those who live alone, to make sure all are accounted for.

Guzman-Mato, now safe in San Juan, says she and her family are still on edge as aftershocks are likely to continue. “In Puerto Rico, you always hear that we’re due for a big one,” she said. “After [Monday’s earthquake] everyone was talking about, ‘alright, get your emergency kits going,’ but we had one day and it came back even harder.”

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Write to Jasmine Aguilera at jasmine.aguilera@time.com.