SANTIAGO, Chile — A strong magnitude-6.8 earthquake struck central Chile on Saturday, causing buildings to sway in the capital of Santiago, but there were no immediate reports of injuries or damage.
The U.S. Geological Survey said the quake struck at 4:31 a.m. about 47 kilometers (29 miles) southwest of Ovalle, a city nearly 300 kilometers (185 miles) northwest of Santiago, at a depth of 36 kilometers (22 miles).
Chile's emergency services office 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 the emergency services, said in a press conference.
He added that Saturday's quake was part of a string of aftershocks from an 8.3-magnitude quake which hit off the coast of Chile on Sept. 16.
That Sept. 16 quake killed at least 11 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.