Puerto Rico Governor Wanda Vazquez declared a state of emergency on Tuesday after a series of earthquakes killed at least one person, toppled buildings and knocked out power to nearly the entire island of more than 3 million people.

The largest of the quakes in the U.S. territory registered at magnitude 6.4, the most powerful to hit the Caribbean island in 102 years.

With two large power plants shut down, drinking water was cut off to at least 300,000 customers, Vazquez told a news conference.