The governor of Puerto Rico, Wanda Vazquez, has declared a state of emergencyand activated the National Guard after several earthquakes hit the Caribbean Island.The strongest, measuring a magnitude 6.4, struck Tuesday along the island's southern coast.The earthquakes knocked out power and killed at least one person, officials and media reported.The U.S. territory is still recovering from two destructive hurricanes in 2017that killed 3,000 people and destroyed a lot of infrastructure across the island.The Puerto Rican government is also dealing with bankruptcy.It hopes to reorganize about $120 billion of debt.Vazquez became governor seven months ago.Large demonstrations pushed former Governor Ricardo Rossello from office.After the quakes, Vazquez asked Puerto Ricans to remain calm.She wrote on Twitter, "We want everyone to be safe...be with your family, implementing your emergency plans."The 6.4-magnitude earthquake on Tuesday struck at a depth of about 10 kilometersalong the island's southern coast, The U.S. Geological Survey said.The epicenter was near the city of Ponce.A 73-year-old man died there after a wall fell on him, the newspaper El Nuevo Dia reported.People on social media described the quake as "super strong" and lasting up to 30 seconds.It was followed by a number of strong aftershocks, including one with a magnitude of 5.8.The effects along the country's southern coast appeared to be major.In Ponce, Mayor Mayita Meléndez told WAPA televisionthat hundreds of people were sitting in the streets of the city.Many did not want to return home for fear of aftershocks or collapsing buildings.A video from WAPA television showed the badly damagedImmaculate Conception church in Guayanilla, about 20 kilometers from Ponce.Only half the church was standing.At least eight homes collapsed in nearby Yauco, El Nuevo Dia reported.Several other earthquakes have struck the island in recent days,including a 5.8-magnitude earthquake Monday.That quake knocked down several houses in Guayanilla and Guanica.It also destroyed the Window of the Caribbean,a rock formation on a beach that was popular among visitors.Jose Ortiz, the chief of the Puerto Rico Electric Power Authorityreported damage to the Central Costa Sur power plant.The power company checked on other stations across the island,and cut off power across the whole island for safety reasons.