Coastlines on both side of the Pacific are braced for tsunamis after a magnitude 8.3 earthquake struck just off the coast of Chile, sending powerful waves flooding into its coastal cities.

Chile’s ministry of the interior and public security said five people had been killed and 1 million evacuated from their homes. A further 20 were injured, but phone networks remain down in parts of the country so the extent of damage and injury is likely to be under-reported.

The first tsunami hit the coastal Chilean city of Tongoy about 8.20pm local time, a little more than 25 minutes after the earthquake. Pictures appear to show the city of Concón, popular with tourists, being deluged by waves.

Chile’s President Michelle Bachelet spoke on national TV, saying Tongoy and Coquimbo had been extensively flooded and damaged. She has declared a catastrophe zone in those areas and mobilised the military to help civilians and prevent looting.

Schools have been closed in several regions. The interior ministry’s national office of emergency has urged people not to return to their homes until they are told it is safe to do so.

But the quake has also sparked fears tsunamis could surge across the Pacific Ocean, with countries as far away Japan, New Zealand, Russia and the US states of California and Hawaii issuing watches, alerts and warnings.

A watch was issued for the California coast: “A tsunami capable of producing strong currents or waves dangerous to persons in or very near the water is expected. The first wave may not be the largest.”

A tsunami advisory for Hawaii said a “major tsunami” was not expected but it warned of sea level changes and strong currents.

The New Zealand minister for civil defence, Nikki Kaye, urged east coast residents in the path of any potential tsunami to stay out of the the ocean, out of boats and off beaches.

The Pacific Tsunami Warning Centre says tsunami waves reaching more than three metres above the tide level are possible in Chile. Waves reaching one to three metres above the tide level are possible in French Polynesia. Waves reaching 0.3 to one metre above the tide level are possible for some coasts of New Zealand, Fiji, Hawaii, Mexico, Ecuador, Peru, Japan, New Caledonia, Samoa, Russia and other Pacific nations.

Waves could take up to 15 hours to reach New Zealand, and 21 hours to reach Russia. 

The power of the initial earthquake was such that it could be felt across swaths of South America.

In the Chilean capital, Santiago, more than 230km from the epicentre of the quake, buildings swayed and thousands fled their homes to take refuge in the streets.

Car alarms were set off in Buenos Aires – more than 1,100km away on the Atlantic side of the South American continent.

Public buildings, including the campus of the University of Buenos Aires, were evacuated. High-rises in the neighbourhoods of Belgrano and Palermo swayed so much that many ran out into the streets. Other Argentinian cities including Rosario and Mendoza reported mass evacuations.

A magnitude 8.8 quake n central Chile in 2010 and ensuing tsunami 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. Just off the coast, the Nazca tectonic plate plunges beneath the South American plate, pushing the towering Andes cordillera to ever-higher altitudes.

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

(The Guardian)