People wait in the street after a tsunami alert in Valparaiso, Chile after the earthquake. Esteban Zuniga / AFP / Getty Images

A man cradles a child on a street outside his residence in Santiago, after the earthquake. Pablo Sanhueza / Reuters

A man recovers items from a store in Concon. The 8.3-magnitude earthquake claimed 8 lives, and forced the evacuation of thousands. Vladimir Rodas / AFP / Getty Images

Strong aftershocks rippled through Chile on Thursday after a magnitude 8.3 earthquake killed at least 11 people and slammed powerful waves into coastal towns, prompting a tsunami warning and forcing nearly one million people from their homes, Interior Minister Jorge Burgos said Thursday.

The quake damaged buildings and knocked out power in the worst-hit areas of central Chile and shook buildings in the capital city of Santiago about 175 miles to the south. The ensuing heavy waves caused flooding in dozens of coastal towns.

Numerous aftershocks, including a magnitude-7 tremor and four above 6, shook the region after the initial earthquake. The U.S. Geological Survey initially reported the earthquake as magnitude 7.9 but quickly revised the reading upward to 8.3. Chilean authorities put the magnitude at 8.4.

“Once again we must confront a powerful blow from nature,” President Michelle Bachelet said in an address to the nation late Wednesday. Bachelet said she planned to travel to the areas worst affected by the quake.

U.S. officials said the quake struck just offshore in the Pacific at 7:54 p.m. local time and was centered in Illapel, about 141 miles north-northwest of Santiago. It said the quake was 4.8 miles below the surface.

People sought safety in the streets of inland cities, while others along the shore took to their cars to get to higher ground. The government ordered evacuations from coastal areas to avoid a repeat of a quake disaster in 2010, when authorities were slow to warn of a tsunami that killed hundreds. As the risk subsided, the government lifted its tsunami warning Thursday morning, some 12 hours after it was initially issued.

Bachelet urged people who had been evacuated from coastal areas to stay on high ground until authorities could fully evaluate the situation early Thursday.

The tremor was so strong that people in Buenos Aires, Argentina, on the other side of the continent, reported feeling it. People in Peru and Brazil also reported feeling the shakes. No injuries were reported outside Chile.

“Earthquake impact is a little like real estate: what matters is location, location, location,” said Susan Hough, a geophysicist with the U.S. Geological Survey. “But it is true that preparedness and risk reduction in Chile is ahead of that in much of the world, and that makes a difference.”

The Pacific Tsunami Warning Center initially issued a tsunami watch for Hawaii, but later downgraded its advisory and said no major tsunami was expected. Tsunami advisories were issued for parts of South America, Southern California and French Polynesia, although waves are generally expected to be small.

As far away as New Zealand, authorities urged residents in eastern coastal areas to stay out of the water and off beaches amid expected “unusually strong currents and unpredictable water flows near the shore.”

Officials ordered people to evacuate low-lying areas along the 2,400 miles of Chile's Pacific shore, from Puerto Aysen in the south to Arica in the north. Fishing boats headed out to sea and cars streamed inland carrying people to higher ground. Santiago's main airport was evacuated as a precaution and authorities announced classes would be suspended in the port city of Valparaiso on Thursday.

Chile state TV showed water flowing in streets of Concon, a coastal town known for its beautiful beaches that is close to Valparaiso. Higher water was also seen in other cities but no destructive high waves had been reported.

Authorities said some adobe houses collapsed in the inland city of Illapel. Mayor Denis Cortés told a local television station that a woman had been killed in the city but declined to give any details.

Electricity was knocked out, leaving the city in darkness. “We are very scared. Our city panicked,” Cortés said.

A magnitude-8.8 quake and ensuing tsunami in central Chile in 2010 killed more than 500 people, destroyed 220,000 homes and washed away docks, riverfronts and seaside resorts. That quake released so much energy, it shortened the Earth's day by a fraction of a second by changing the planet's rotation.

Chile is one of the world's most earthquake-prone countries because just off the coast, the Nazca tectonic plate plunges beneath the South American plate, pushing the towering Andes cordillera to ever-higher altitudes. It is part of the Ring of Fire, which includes more than 450 volcanoes on the Pacific Rim.

The strongest earthquake ever recorded on Earth happened in Chile — a magnitude-9.5 tremor in 1960 that killed more than 5,000 people.

Al Jazeera and wire services