- Because of Sunday's gargantuan quake, planet Earth is
ringing like a church bell.
- You can't hear it, but it's being measured at seismic
stations around the world, including Columbia University's Lamont-Doherty
Earth Observatory in Palisades, N.Y.
- It will last for three days, perhaps longer.
- The quake, which measured 9.0 on the Richter scale, was
caused by the shifting of geological plates along a 600-mile area.
- This changed the Earth's mass.
- As the mass returns to normal, it moves back and forth,
much like a church bell when struck by a tong, said Stony Brook geophysicist
- The phenomenon was observed after the 9.5-magnitude quake
in Chile in 1960 and the 9.2 magnitude temblor in Alaska in 1964.
- After both quakes, the ringing lasted for three days,
getting smaller every day.
- The ringing now should last about that long and there's
no need to worry.
- Scientists say it's harmless. "Everything will calm
down. We don't have any reason to be scared," said Constantin Cranganu,
a geophysics prof at Brooklyn College.
- Of far greater concern is the strong possibility of aftershocks
as the geological plates adjust.
- These could measure 6.0 to 7.0 on the Richter scale,
the size of many earthquakes, and so could cause additional damage, said
Lamont-Doherty seismologist Art Lerner-Lam.
- He said, however, that it's unlikely the tremors will
trigger the tsunamis, or killer waves, that caused most of the death and
destruction in Sunday's quake.
- Lerner-Lam said the aftershocks could last for months,
although their size and frequency will die down.
- The quake caused a shift in the Earth's rotation, as
the change in the planet's mass altered the effect of the pull of gravity
on the Earth.
- But not to worry. The same thing happens in the summer
and winter. It's harmless and it shouldn't last long.
- A tsunami last crossed the Indian Ocean in 1509. Scientists
had not expected anything close to the quake and killer waves that struck
Sunday because 90 percent of tsunamis occur in the Pacific Ocean, where
there are warning systems.
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