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Chilean M8.2 Earthquake May Be Forewarning Of A Larger Event

April 2, 2014
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Lawrence LeBlond for redOrbit.com – Your Universe Online

Chile is beginning to dig out from a massive 8.2 magnitude earthquake that struck the region at 8:46 p.m. local time Tuesday evening about 52 miles northwest of the mining town of Iquique, according to the USGS. At least five people are confirmed dead and tens of thousands have been evacuated from their homes.

The earthquake touched off tsunami warnings and, according to the BBC, waves up to six feet battered the shoreline in some areas. Widespread power outages, fires and landslides were also complicating rescue efforts. As well, numerous aftershocks were felt throughout the night, including a 6.2 tremor.

Several regions have been declared disaster areas by the government in hopes of “avoiding instances of looting and disorder.”

Shortly after the quake, President Michelle Bachelet promised troops and police reinforcement would be sent to maintain public order during rebuilding and repair.

“We’re leaving with the children and what we can, but everything is clogged up by people fleeing buildings by the beach,” said 32-year old Liliana Arriaza, who was driving away with her three children, according to a Reuters report.

Bachelet said the country had “faced the emergency well” and called on those in the affected regions “to keep calm and follow instructions from the authorities.”

The country’s interior minister told Chilean TV that the quake allowed 300 woman inmates to escape from a prison in Iquique. Officials later said that 26 had been recaptured.

At press time, the government said that 50 percent of the power has been restored to affected regions.

While this was already considered a massive earthquake, geologists say that an even bigger temblor may be lurking in the region’s future.

“This magnitude 8.2 is not the large earthquake that we were expecting in this area,” Mark Simons, a geophysicist at Caltech in Pasadena, California, told CNN. “We’re expecting a potentially even larger earthquake.”

“We do not know when it’s going to occur,” he maintained.

To give a better idea why geologists believe a larger quake is in Chile’s forecast, a little science is needed.

Chile sits on an arc of volcanoes and fault lines that circles the Pacific Ocean. This circle, known as the “Pacific Ring of Fire,” sees frequent earthquakes and volcanic eruptions. And Chile is no stranger to frequent tremors.

Since 1973, more than a dozen magnitude-7.0 or larger quakes have struck Chile. In more recent years, an M8.8 temblor killed 500 people when it rocked the region in 2010. The quake was so violent, it moved the whole city about 10 feet to the west.

Simons said Tuesday’s quake was of much interest because the fault line along Chile’s coast has been in constant shift for the past 140 years.

In recent weeks, as many as 100 smaller quakes have been recorded. But late last month the region was affected by two larger tremors – a 6.7- and a 6.1-m.

Simons explains that when a quake occurs the surface can rupture and the two sides of the fault slip past each other. However, he said that no surface rupture occurred in the latest quake. And, he added, it “hasn’t ruptured in 140-odd years.”

He said it is only a matter of time, however, until an earthquake causes surface rupture.

“We expect another 8.8-8.9 earthquake here sometime in the future,” Simons told CNN. “[But,] it may not occur for many, many years.”

As for last night’s temblor, the Pacific Tsunami Warning Center issued an initial warning for Chile, Peru, Ecuador, Colombia and Panama. However, all warnings were later lifted except for Chile and Peru.

Tsunami watches were also issued for Costa Rica, Nicaragua, El Salvador, Guatemala, Mexico and Honduras. As well, a tsunami advisory was issued for Hawaii, although no disaster was expected to hit the island state.

“Sea level changes and strong currents may occur along all coasts that could be a hazard to swimmers and boaters as well as to persons near the shore at beaches and in harbors and marinas,” the PTWC said in a statement.

Japan’s Meteorological Agency said that a tsunami of up to three feet might hit Japan’s Pacific Coast about 5:00 a.m. Thursday. After collecting more data it said it may issue a tsunami advisory early Thursday.

Patrick Moore, a British expatriate living in Antofagasta, Chile told the BBC that there had been several tremors since the last quarter of 2013.

“But this earthquake, even with the increased distance, seemed to last a lot longer,” Moore said. “I knew it was bad so I immediately went online to see what had happened and saw a tsunami warning that’s been put in place which confirmed my fears that it was a big one.”

The largest earthquake to hit Chile in recent memory was the 1960 9.5-magnitude event that caused about 1,655 deaths as well as a tsunami that hit Hawaii and Japan. By comparison, the 2011 Japan earthquake that killed 15,000 people and caused a nuclear disaster was a 9.0-magnitude temblor.


Source: Lawrence LeBlond for redOrbit.com - Your Universe Online



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