Chile declared a state of emergency in the central region Thursday after a magnitude-8.3 earthquake killed 11 people and caused widespread disruption.

President Michelle Bachelet declared the state of emergency for the region around the port city of Coquimbo, near the epicentre of the quake which struck late Wednesday, daily El Mercurio reported, citing Interior Minister Jorge Burgos.

Hundreds of soldiers would be sent to the affected region.

Parts of the country began to return to normal after a night of strong aftershocks and a small tsunami that flooded some coastal homes and businesses.

About 1 million people were evacuated from their homes in fear of a tsunami, as tsunami warnings were issued for areas all along the Pacific coast.

Small tsunami waves reached the Japanese coast early Friday morning local time.

Waves of between 10 and 40 centimetres were observed on the east coast, Japan's meteorological agency said.

"The tsunami threat has now largely passed," the Pacific Tsunami Warning Center reported in what it said would be its final threat message.

Ricardo Toro, director of Chile's ONEMI organization for disaster management, said 11 people were confirmed dead in the quake, which struck Wednesday near the coastal town of Illapel at 22:54 GMT.

Burgos said earlier that some of the victims were crushed by collapsing walls and others died of heart attacks.

More than 600 people were still lodged in hotels Thursday and 180 buildings were destroyed by the earthquake, the organization for disaster management said.

The quake disrupted transport and communications and produced waves as high as 5 metres that flooded past containment barriers to reach some homes and businesses, even pushing boats on to city streets.

Bachelet travelled to Coquimbo, 460 kilometers north of Santiago, surveying damage in the region most affected by the quake and tsunami.

There, she praised a rapid response by emergency services, and promised agencies would work quickly to help those affected by the earthquake and its aftermath.

"We know the pain it causes, and often the anger as well, and so for that we are working as quickly as possible," she said.

Bachelet canceled all public appearances Thursday, including the launch of the country's Independence Day celebrations.

More than 100 aftershocks - the strongest a magnitude 7.6 - added to the fears among evacuees.

Roads were cut off by mudslides. An estimated 100,000 families were without electricity, according to the government, and many buildings collapsed.

"There are many collapsed walls - many houses, mainly those made of adobe, whose walls were brought to the ground," Bernardo Leyton, mayor of Canela near the epicentre, told the radio station Bio Bio.

"People are very scared," Leyton said.

The mayor of Illapel, the town closest to the epicentre, said a woman died there after being hit by a collapsing wall, according to La Tercera newspaper.

Deputy Interior Minister Mahmud Aleuy reported that another woman died in an avalanche while three men died of heart attacks. It was unclear how the other victims died.

The quake was the sixth largest in the country's history, Aleuy said.

The US Geological Survey measured the quake's magnitude at 8.3 while the Chilean National Quake Centre said it was 8.4.

The quake was felt as far away as Buenos Aires, a distance of more than 1,200 kilometres. Several buildings in the Argentinian capital were preventively evacuated.

Schools were closed Thursday in much of Chile.

Chile is a quake-prone country. On February 27, 2010, a magnitude-8.8 quake and resulting tsunami killed more than 500 people and caused major damage across the country.

A magnitude-7.8 quake claimed the lives of 28,000 people in 1939. The largest earthquake ever measured - 9.5 on the Richter scale - also occurred in Chile, killing 1,655 people in 1960.