Coquimbo (Chile) (AFP) - Traumatized Chileans described Thursday the terrifying moment a powerful earthquake hit, killing at least 12 people and triggering tsunami waves that ravaged long stretches of the coast.
The 8.3-magnitude offshore earthquake Wednesday evening was the sixth strongest in the history of geologically volatile Chile and the most powerful anywhere in the world this year, officials said.
Close to one million people were evacuated from Pacific coastal areas as a precaution as Chile sounded a tsunami alert, with warnings issued as far away as Japan and New Zealand.
Residents in hardest-hit central Chile took refuge on high ground as aftershocks jolted the country all night and into Thursday.
Maria Zamorano, 60, recounted how she and her large family ran from the shoreline in Coquimbo to save themselves from the surging tsunami waves.
"If we had stayed here we would have perished," she told AFP, as people slowly and warily returned to see what was left of their homes.
The quake occurred at a shallow depth and the epicenter was 228 kilometers (about 140 miles) north of the capital Santiago, a city of 6.6 million people, where there were scenes of pandemonium as thousands fled swaying buildings.
In the hours that followed, tsunami waves of up to 4.5 meters (15 feet) came crashing onshore in Coquimbo region, 400 kilometers north of Santiago, causing extensive damage to the region's port. Eight of the 12 victims were in Coquimbo.
Fishing boats, trucks, cars and the remains of dozens of houses were among the debris bobbing up and down in Coquimbo city's wrecked waterfront on Thursday.
There were similar scenes of destruction in the badly hit coastal town of Illapel.
"It was a nightmare," Maria Ramirez told AFP as she swept up debris outside her house.
"We felt the tremors for a long time, too long. And then all the aftershocks -- it was terrible.
"I couldn't stay standing, but luckily we made it out alive."
- Ring of fire -
President Michelle Bachelet headed to the quake-hit area to assess the relief efforts and Secretary of State John Kerry said the United States was ready to help.
"We know this is a very difficult situation," Bachelet said after meeting a group of local fishermen in Coquimbo.
"But we wish to salute the enormous cooperation of the population which ensured that -- despite the scale of this earthquake -- there are thankfully few victims."
Interior Minister Jorge Burgos said five people were missing and there were still more than 600 people languishing in shelters.
Hundreds of homes were declared uninhabitable or destroyed, as authorities tot up the human, emotional and financial cost.
Chile lies on what is known as the "Ring of Fire" -- an arc of fault lines that circles the Pacific Basin and is prone to frequent earthquakes and volcanic eruptions.
In February 2010, an 8.8-magnitude quake off the southern Chilean coast killed more than 500 people and inflicted an estimated $30 billion in damage.
The Hawaii-based Pacific Tsunami Warning Center had warned that tsunami waves were possible this time in French Polynesia, Hawaii and California, as well as smaller waves as far afield as Japan and New Zealand.
A minor tsunami was monitored in northern Japan early Friday, authorities there said.
- 'Horrific moment' -
In Illapel, a town of 30,000, daybreak revealed the damage done, with power knocked out, shacks destroyed, store shelves overturned and the local cemetery a chaos of broken crosses, vases and coffins.
"It was the most horrific moment, a terrible thing," local resident Ana Cortes, 35, told AFP. "Everything just kept moving, for the longest time."
Facebook said it had activated a geolocation tool allowing people in Chile to reassure friends and loved ones.
The Safety Check tool is accessed through Facebook's regular interface, and lets members check whether their contacts are in a disaster zone, signal their own presence and let others know they are safe and well.