Deadly 8.2 earthquake rattles Chilean coast, touches off tsunami

A powerful megathrust earthquake struck off the coast of northern Chile on Tuesday night, killing six people and touching off a tsunami that impacted up and down the coast for hundreds of kilometres.

The magnitude 8.2 quake struck at 7:46 p.m. Eastern Time, about 95 kilometres northwest of the city of Iquique, in the north of Chile. Based on reports submitted to the US Geological Survey, the quake intensity (exactly how bad the shaking was perceived by the people in the area) continued to grow throughout the night until it reached the second highest rating on the Mercalli Intensity Scale. The temblor was so powerful due to being very shallow, focused only about 10 kilometres under the sea floor, in an area of the boundary between the Nazca plate and the South American plate that's known for being a particularly strong focus for stress between the plates. The result was a massive 'megathrust' quake.

Just as what happened with the megathrust quake off the coast of Japan three years ago, the sudden, powerful shift in such a large amount of earth set off a tsunami that spread out along the coastline. The tsunami set off warnings and watches throughout the Pacific Ocean, impacting on the coast just 20 minutes later in Iquique, and as far north as the coast of Peru and as far away as Coquimbo, over 1,300 kilometres to the south. According to Earthquake-Reports.com, the mayor of Iquique said that tsunami washed up to 100 metres on shore, or roughly three city blocks.

The U.S. Pacific Tsunami Warning Center produced this near-realtime model of the waves from the tsunami as they spread throughout the Pacific Ocean Tuesday night:

Most of Iquique was without power immediately following the quake, and there were reports of several fires burning in the area. According to the Chilean government, six people died during the earthquake — apparently due to heart attacks or in landslides touched off by the quake. Earthquake-Reports.com also reports three others were seriously injured.

Chile's president, Michelle Bachelet, declared a state of emergency in the northern provinces of the country, to deal with the relief efforts.

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Dozens of aftershocks have struck the area in just the six hours since the main quake, with over 20 measuring at least magnitude 4.5, and including a magnitude 6.2 quake just along the coast. This massive quake follows two weeks of tremors that have been shaking the area ever since a magnitude 6.7 earthquake struck the same region of the fault on March 16th. Given the number and magnitude of aftershocks so far, it's likely that the area could suffer more strong earthquakes, and possibly above magnitude 7.0, before the fault calms down again.

Although this quake was extremely powerful, it caused surprisingly little damage and very few casualties compared to what could have resulted from it (similar to the earthquake off the coast of northern California in early March). Chile is apparently very well prepared for earthquakes and tsunamis, due to suffering through a history of temblors over the years. However, even so, if this quake had touched off just a bit closer to the coast, the results might have been similar to the devastating 2010 Chile Earthquake that struck further down the coastline.

(Images courtesy: USGS, NOAA)

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