- LOS ANGELES (Reuters) - California's
largest earthquake in four years struck on Monday, causing Planet Earth
to ring "like a bell" and mountains to grow a foot taller, geologists
said on Monday.
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- The magnitude 6.5 quake hit near the coastal city of
San Simeon almost exactly half way between San Francisco and Los Angeles,
setting high-rise buildings swaying in both cities.
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- Earthquakes relieve pressure between clashing continental
plates. The plates float on the earth's mantle, which has a putty like
consistency and moves as the earth's core heats it.
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- On Monday one piece of crust shoved beneath another about
4.75 miles beneath the surface of the earth and at the intersection of
the Pacific and North American plates, U.S. Geological Survey seismologists
said
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- That sent tremors along America's west coast and beyond.
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- "For an earthquake this size, every single sand
grain on the planet dances to the music of those seismic waves," the
Geological Survey spokesman Ross Stein said at a news conference.
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- "You may not be able to feel them, but the entire
planet is rung like a bell."
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- The Monday earthquake struck on what is believed to be
the San Simeon thrust fault. Pressure in a thrust fault is relieved when
one piece of earth pushes up on top of another, compared with lateral faults
-- like the famous San Andreas -- in which two piece of crust slide next
to one another.
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- Thrust faults produce mountains, and the San Simeon quake
probably improved the view from the nearby hills, Stein said because, "mountains
have probably been pushed up about a foot or so by this earthquake."
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- The tremor was the biggest in California since 1999,
when the Hector Mine quake crashed through the desert east of Los Angeles,
and it packed about half the power of the Northridge earthquake which shook
Los Angeles a decade ago.
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- Earthquake power is measured on a scale which increases
exponentially, so at 6.7 the Northridge quake was about twice as powerful
as the 6.5-magnitude San Simeon quake.
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- The Northridge quake was also one of the costliest disasters
in U.S. history, causing over $40 billion of damage since it shook a heavily
populated area.
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- Geologists expect smaller aftershocks of magnitude 5
to continue for days, weeks and longer, and there is a 5 percent to 10
percent chance that Monday's quake was a precursor to a bigger one.
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- The plates have created a patchwork of faults, said Susan
Hough, a seismologist at the United States Geological Survey in the Los
Angeles suburb of Pasadena.
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- "The crust is getting mangled over a zone,"
she said. "As the plates move they are sort of grinding California
into ribbons," she said.
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- Eventually the movement will carve Mexico's Baja California,
the peninsula that juts south below San Diego, California, off from the
rest of Mexico.
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- But California is not going anywhere quickly.
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