The quake shook buildings in the capital Santiago, causing panic among residents, whose frantic phone calls clogged cellular networks and land lines, AFP correspondents said. But "there are no preliminary reports of injuries, interruption of basic services or infrastructure damage," the National Emergency Office (Onemi) said.
"No region has reported emergency situations caused by this earthquake," one official, Miguel Ortiz of Onemi's early warning center, told a news conference.
The quake was unlikely to cause a tsunami, the navy said. It struck at 1:20 PM at a depth of 90.8 kilometers, according to the US Geological Survey. Chile's National Seismological Service said the epicenter was 38 kilometers southeast of the city of Curico, which is itself some 200 kilometers south of Santiago.
Both agencies put the magnitude at 6.4. Residents reported feeling the quake across nearly 1,000 kilometers, from the northern region of Coquimbo to the southern region of La Araucania.
In Santiago, a city of seven million people, initial moments of panic were followed by a return to normal daily life. Phone service briefly collapsed but was restored after several minutes.
Chile is one of the world's most earthquake-prone countries. It sits on the Pacific Ocean's "Ring of Fire," a seismically turbulent region where many of Earth's volcanic eruptions and earthquakes occur.
In 2010, an 8.8-magnitude quake and subsequent tsunami killed more than 500 people.