Our live coverage of this story has ended. You can read more about the Puerto Rico earthquakes here.
FEMA, the Federal Emergency Management Agency, received Puerto Rico's request for an emergency declaration from the earthquake that occurred earlier Tuesday, and that request is under consideration, the agency said.
Acting FEMA Administrator Pete Gaynor has been in constant communication and coordination with Puerto Rico Gov. Wanda Vazquez, FEMA said.
FEMA personnel in Puerto Rico are working closely with the Puerto Rico Emergency Management Bureau and have deployed two Incident Management Assistance Teams to the island, the agency said. Additionally, FEMA activated its Response Operations Cell in Washington and Regional Response Coordination Center in New York to assist with any additional resource needs.
"FEMA remains committed to supporting the government of Puerto Rico with its ongoing recovery efforts from Hurricanes Irma and Maria and to helping people before, during and after disasters," the agency said.
The earthquakes along the southern coast of Puerto Rico could cost the island up to $3.1 billion in economic losses, according to Chuck Watson, an analyst with Enki, a disaster research group.
The estimate accounts for damage to both public and private property, as well as lost tourism, wages and business due to power outages.
Watson said the estimate is high due to multiple aftershocks hitting already weak structures, as well as the lingering effects of Hurricane Maria. Some of the infrastructure damage from the 2017 storm has still not been repaired, according to the American Society of Civil Engineers.
CNN’s Angela Barajas contributed to this report.
Puerto Rico's Gov. Wanda Vázquez Garced announced Tuesday that $130 million in emergency aid has been made available in response to both earthquakes.
The governor also pleaded for everyone to remain calm and to prepare for any future seismic activity at a Tuesday morning news conference.
“We are talking about a situation Puerto Rico had never been exposed to in 102 years,” said Vázquez.
Vázquez said preliminary findings show that 255 people have sought refuge at different shelters in the southern part of the island. Close to 300,000 clients are without water service, she said.
Vazquez said there are power outages throughout the southern part of the island but engineers are already working on reestablishing service. Power plants had automatically shut off as a safety mechanism following Monday's quake, but Tuesday's quake caused damage to them, according to the governor.
Damage to some roads was reported -- but there were no reports of significant damage to bridges or dams. “We have responded to many difficult situations, and here we are once again and we will do it the same way, helping our people move forward.” said Vázquez.
President Donald Trump has been briefed on the earthquakes in Puerto Rico.
"The President has been briefed on the earthquakes that Puerto Rico has experienced over the past month, including the earthquake early this morning," spokesman Judd Deere said.
"Administration officials, including FEMA Administrator Pete Gaynor, have been in touch with the governor and her team today, and we will continue to monitor the effects and coordinate with Puerto Rico officials."
New York Gov. Andrew Cuomo is redirecting personnel from the New York Power Authority who were already deployed in Puerto Rico to help restore power following several earthquakes that have hit the island, a statement from his office says.
"During difficult times, the State of New York always stands with and supports our brothers and sisters in Puerto Rico -- and today is no different," Gov. Cuomo said.
The NYPA already had a team of ten technical power experts on the island assisting Puerto Rico since Hurricane Maria. The team “has been working to address recent blackouts and stabilize the island's power systems to avoid power outages,” the statement says.
“Once this team has completed its work to help restore power after the earthquake, it will resume its collaborative efforts with PREPA to harden Puerto Rico's electric system so it is better prepared to withstand all kinds of natural disasters in the future.”
Riko Gonzalez described the 6.0 and 6.4 earthquakes as "horrible."
"People are afraid to go to bed to then be woken up to worse earthquakes than the day before."
Gonzalez shared a number of photos on Facebook that show the rubble and destruction around Yauco, a city in southwest Puerto Rico.
"Luckily (communications) are up so we check on each other periodically. But if it wasn’t for that there would be panic," Gonzalez said.
The earthquakes on Monday and Tuesday struck to the southwest of Puerto Rico, at the opposite end of the island from its capital, San Juan.
The US Geological Survey said that they struck in the area where the North American tectonic plate converges with the Caribbean tectonic plate.
Gov. Wanda Vazquez Garced has signed a state of emergency declaration for the island, thus activating the National Guard of Puerto Rico.