SANTIAGO, Chile -- A strong magnitude-6.8 earthquake struck north-central Chile on Saturday, causing buildings to sway in the capital of Santiago.
The U.S. Geological Survey said the quake struck at 4:31 a.m. about 29 miles (47 kilometers) southwest of Ovalle, a city 185 miles (300 kilometers) northwest of Santiago, at a depth of 22 miles (36 kilometers).
Chile's Navy first alerted, but later discounted, the possibility of a small tsunami.
"The situation in the region of the epicenter is now in a state of normality," Ricardo Toro, the head of Chile's emergency services, said in a press conference.
He added Saturday's quake was part of a string of aftershocks from an 8.3-magnitude quake that hit off the coast of Chile on Sept. 16.
That Sept. 16 quake killed 15 people, forced the evacuation of more than 1 million from coastal areas and caused much anxiety. But seismologists said Chile's heavy investment in the structural reinforcement of buildings and its constant refinement of a tsunami alert system helped prevent what would have been a catastrophe in less prepared nations.
Chile is highly earthquake-prone. In 2010, a devastating 8.8-magnitude quake struck the country, one of the strongest ever recorded. The quake and the tsunami it unleashed killed more than 500 people, destroyed 220,000 homes and washed away docks, riverfronts and seaside resorts.
The strongest earthquake ever recorded also happened in Chile: a devastating magnitude-9.5 one in 1960 that killed more than 5,000 people.