Coastal Chile has a history of very large earthquakes. Since 1973, there have been 13 events of magnitude 7.0 or greater. The February 27 shock originated about 230 km north of the source region of the magnitude 9.5 earthquake of May, 1960 – the largest earthquake worldwide in the last 200 years or more. This giant earthquake spawned a tsunami that engulfed the Pacific Ocean. An estimated 1600 lives were lost to the 1960 earthquake and tsunami in Chile, and the 1960 tsunami took another 200 lives among Japan, Hawaii, and the Philippines. Approximately 870 km to the north of the February 27 earthquake is the source region of the magnitude 8.5 earthquake of November, 1922. This great quake significantly impacted central Chile, killing several hundred people and causing severe property damage. The 1922 quake generated a 9-meter local tsunami that inundated the Chile coast near the town of Coquimbo; the tsunami also crossed the Pacific, washing away boats in Hilo harbor, Hawaii. The magnitude 8.8 earthquake of February 27, 2010 ruptured the portion of the South American subduction zone separating these two massive historical earthquakes.
A large vigorous aftershock sequence can be expected from this earthquake.
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There were fears tonight a tsunami could wreak devastation across the Pacific after a massive earthquake in Chile.
More than 120 people were killed when the 8.8 magnitude quake struck the South American country early today.
It sent shockwaves out from the epicentre 70 miles from Chile's second city Concepcion, causing buildings and bridges to collapse and catch fire.
The quake, the most powerful to hit the nation in 50 years, struck around 200 miles south west of the capital Santiago.
As powerful aftershocks caused further problems along the coast, tsunami warnings were issued in 53 countries around the Pacific Ocean - roughly a quarter of the globe.
The tsunami could strike any country in the Pacific, with the US state of Hawaii potentially facing its largest waves since 1964.
Asian, Australian and New Zealand shores were at risk along with the US West Coast and Alaska.
With the Chilean president declaring a "state of catastrophe" and the death toll continuing to rise, British aid organisations deployed teams to help in the aftermath.
Chile is at high risk of earthquakes because it lies on the boundary between the Pacific plate and the South American plate.
The latest quake happened after the Pacific plate pushed down on to the South American plate.
According to seismologists, there is usually around one quake of a magnitude of eight a year while one reaching 8.8 would only be expected every few years.
Dr Brian Baptie of the British Geological Survey said: "In global terms this is a very rare quake.
"Chile has experienced some very big quakes in the past.
"It was about 124 miles north east of the largest earthquake ever recorded - 9.5 - in 1960, which resulted in a destructive tsunami that killed many thousands of people around the Pacific."
He said a tsunami wave was observed at Valparaiso, 124 miles north of the epicentre, about 20 minutes after the earthquake.
"Tsunami waves in the deep ocean travel about the same speed as a jet plane and would take about 15 hours to reach Hawaii and about 20 hours to reach the other side of the Pacific," he added.
The devastating tsunami which hit Asia in 2004 measured 9.3 on the Richter scale, making it the second largest ever after the 1960 Chile quake.
Dr David Rothery, from the department of earth and environmental sciences at the Open University, said: "This morning's magnitude 8.8 earthquake close to the Chilean coast has caused a tsunami that is now radiating away from the epicentre and travelling at several hundred kilometres per hour across the Pacific ocean.
"Because the epicentre was under the sea, the sudden jerking of the sea-floor displaced water and triggered a tsunami."
In London, the Chilean ambassador Rafael Moreno thanked the international community for offers of support but said the situation was "under control".
He said strict regulations about earthquake-proofing new buildings would have helped to limit the damage.
Staff at the embassy in central London have been fielding calls from British-based Chileans who are worried about their families and have been unable to reach them.
A lack of power has limited communications and the ambassador himself was yet to hear from his sister in Concepcion.
He said: "The situation is totally under control. We have good mechanisms (for coping with earthquakes).
"The lines are down, most of them, because of the electricity problem so we communicate through mobiles or Skype.
"We are receiving a lot of phone calls here at the embassy. I came here as soon as I heard the news.
"If people have a need, call the embassy. The embassy is open, we will provide any type of support required."
About 65,000 British tourists visit Chile each year, according to the country's tourist authority.
The Foreign Office updated its travel information for people planning to go to Chile, saying: "The Foreign and Commonwealth Office is in contact with our embassy in Santiago in order to establish the facts on the ground.
"Communications are sporadic. We will update this advice over the next few hours."
The FCO issued revised travel advice, warning that "all but essential travel" to the regions of Biobio, Maule and Araucania should be avoided.
"The capital Santiago has also been affected with some damage to older buildings and at least two road flyovers have collapsed," it said.
"If you are a British national in Chile, you should follow the advice of the local authorities.
"The British Embassy is so far unable to receive calls.
"If you are in Chile and require assistance or if you know someone in the affected areas of Chile, please ring the Foreign and Commonwealth Office on +44 207 008 0000."
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