7.2-Magnitude Earthquake Rocks Chile

Tsunami alert issued after largest aftershock since calamitous Feb. temblor

The largest aftershock since Chile's devastating earthquake rocked the South American country Thursday, minutes before the inauguration of President Sebastian Pinera.

The 7.2-magnitude aftershock was stronger than the Jan. 12 quake that devastated the Haitian capital. It happened along the same fault zone as Chile's magnitude-8.8 quake on Feb. 27, said geophysicist Don Blakeman at the U.S. Geological Survey in Golden, Colorado.

Chile's emergency office said there were no immediate reports of damage, but the Chilean Navy issued a tsunami alert.

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Chilean Quake Likely Shifted Earth’s Axis, NASA Scientist Says

From BusinessWeek
By Alex Morales

The earthquake that killed more than 700 people in Chile on Feb. 27 probably shifted the Earth’s axis and shortened the day, a National Aeronautics and Space Administration scientist said.

Earthquakes can involve shifting hundreds of kilometers of rock by several meters, changing the distribution of mass on the planet. This affects the Earth’s rotation, said Richard Gross, a geophysicist at NASA’s Jet Propulsion Laboratory in Pasadena, California, who uses a computer model to calculate the effects.

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Chilean Earthquake Hints at Dangers of 'Big One' for USA

From USA Today
By William M. Welch, Dan Vergano and Chris Hawley, USA TODAY

One of the really "Big Ones" to shake the United States was a magnitude-9.0 earthquake along the Pacific Northwest coast more than 300 years ago, before the arrival of huge numbers of people and development, that sent a catastrophic tsunami to Japan.

Were something like that 1700 quake to occur today — and it certainly could, seismologists say — enormous destruction and loss of life would result in a region that is home now to big cities and millions of people.

The magnitude-8.8 earthquake that rocked Chile and sent tsunami fears across the Pacific on Saturday — nearly seven weeks after the enormously deadly quake that destroyed parts of Haiti— serves as a vivid reminder of the perils posed to the United States by countless fault lines and shifting plates.

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