A 6.4-magnitude earthquake struck Puerto Rico before dawn on Tuesday, killing one man, injuring at least eight other people and collapsing buildings in the southern part of the island.
The quake was followed by a series of strong aftershocks, part of a 10-day series of temblors spawned by the grinding of tectonic plates along three faults beneath southern Puerto Rico. Seismologists say it's impossible to predict when the quakes will stop.
The 6.4-magnitude quake cut power as power plants shut down to protect themselves. Authorities said two plants suffered light damage and they expected power to be restored later Tuesday.
It was the second straight day in which a significant quake struck the island. On Monday, a 5.8 magnitude quake shook the island, causing minor damage.
Puerto Rico Gov. Wanda Vazquez signed a series of executive orders Tuesday declaring a state of emergency on the island and activating the National Guard.
The Associated Press reports that a 73-year-old man was killed when a wall in his home collapsed on top of him. Eight other people were injured in the city of Ponce, according to WAPA-TV in Puerto Rico.
A tsunami alert was issued in the moments after the earthquake but was quickly canceled.
The earthquakes on Tuesday came just a day after a 5.8-magnitude quake collapsed five homes on the south side of the island. The UPRM Meteorological Laboratory shared a photo on Twitter of Punta Ventana before and after the earthquake. That earthquake also caused a small landslide and some power outages, but no injuries were reported.