Starting on December 28, 2019,[7] and progressing into 2020, the southwestern part of the island of Puerto Rico was struck by an earthquake swarm,[8] including 11 that were of magnitude 5 or greater.

[12][13] A 5.8 Mw earthquake the previous day caused the destruction of a natural arch, a tourist attraction at Punta Ventana in Guayanilla.

[14] A 5.9 Mw aftershock on Saturday, January 11, damaged many structures, including several historical buildings as well as modern high-rises in the city of Ponce.

[17] Damage to government structures was calculated in the hundreds of millions[8] and financial losses were estimated in $3.1 billion.

[3] A power plant that supplied over a quarter of Puerto Rico's energy needs was badly damaged and was shut down, with repairs estimated to take at least a year.

On January 8, the day after the main quake, the Ponce municipal government registered 1,111 residents in city shelters, "not including hundreds more" who drove to government-designated meeting sites, such as Estadio Paquito Montaner, to sleep in their cars.

[19] Late January 7, FEMA confirmed that US president Donald Trump had issued a (non-disaster[20]) emergency declaration with a $5 million cap.

[23] The government set up a central command center, where all pertinent state and municipal dependencies supporting the relief effort were to set up base and coordinate activities at the Polideportivo Frankie Colon in Urbanización Los Caobos, Barrio Bucaná, Ponce.

[38] A male resident of Urbanización Jardines del Caribe,[39] in the city of Ponce, lost his life as a direct result of the January 7 quake; additionally, eight other people in the area were injured.

[43] There were refugees in 28 government-sponsored refugee centers in the southern and central Puerto Rico municipalities of Yauco, Guánica, Ponce, Peñuelas, Guayanilla, Utuado, Maricao, Juana Díaz, Adjuntas, Sabana Grande, San Germán, Lajas, Jayuya and Mayagüez.

[49] Numerous authorities pointed to the emotional toll on the people, particularly on entire families who had been left homeless.

[50][51][52] The January 7 quake destroyed numerous structures, including the Agripina Seda Elementary School in Guánica[53] and the Inmaculada Concepción Church in Guayanilla.

[54][55] Also severely damaged by the January 7 quake were the La Guancha Recreational and Cultural Complex, which was made inoperable and where 24 establishments had to shut down their operations,[56] and Auditorio Juan Pachín Vicéns.

For example, the José Julián Acosta Theater Arts School in San Juan was deemed partially unusable due to structural safety concerns, with classes being moved to the nearby Carnegie Library temporarily.

[72] Among damage to infrastructure, the 5.9 aftershock quake the morning of January 11 created a crack in a bridge, and was expected to delay restoration of power.

[76] On January 17, Puerto Rico governor fired three members of her Cabinet after a group of Puerto Ricans broke into an enormous State warehouse in the La Guancha sector of Barrio Playa in Ponce and found it fully stocked with emergency items including cots, gas stoves, batteries, water, baby formula, diapers that had been stored there since after Hurricane Maria, and which the governor had not been made aware of.

[77][78] The governor nominated the Adjutant General of the Puerto Rico National Guard to take over the post of fired Office of Emergency Management Secretary and ordered him to immediately move the items to the refugee centers of the municipalities affected by the earthquake and to distribute them to those people needing them.

[79][80][81] In the aftermath of the main quake and its major aftershocks, thousands of residents, including many whose homes had not been damaged, developed seismophobia and continued sleeping outdoors weeks after the earthquake of January 7.