Chile Quake in 'Elite Class' Like 2004 Asian Quake  The
magnitude 8.8 quake is of a type considered the most powerful on
the planet.  Members of a family, with sacks containing food,
take a rest in front of a collapsed building in Concepcion,
Chile, Sunday, Feb. 28, 2010. A 8.8-magnitude earthquake hit
Chile early Saturday. Associated Press logo  AP Science Writer
The magnitude-8.8 quake was a type called a "megathrust,"
considered the most powerful earthquake on the planet.
Megathrusts occur when one tectonic plate dives beneath another.
Saturday's tremor unleashed about 50 gigatons of energy and
broke about 340 miles of the fault zone, according to the U.S.
Geological Survey's National Earthquake Information Center.  The
quake's epicenter was offshore and occurred about 140 miles
north of the largest earthquake ever recorded - a magnitude-9.5
that killed about 1,600 people in Chile and scores of others in
the Pacific in 1960.  "It's part of an elite class of giant
earthquakes," said USGS geologist Brian A