San Andreas Rumblings Mystify Scientists
Larry O'Hanlon
Discovery Channel
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Mysterious rumblings detected inside and above the San Andreas Fault at Parkfield, Calif., have seismologists scrambling for answers, some of which might point to a new way to forecast earthquakes.
The unexplained rumblings are known by various names to seismologists, including "silent earthquakes," "slow slip events," "Episodic Tremor and Slip," or "non-volcanic tremors."
They don't jolt like earthquakes and seem to resemble the chaotic vibrations produced by a volcano's plumbing system, except that there's no live volcano anywhere near Parkfield.
"If you could listen to it, it'd be more like a tone, not a bang like an earthquake," said Paul Segall, a "silent earthquake" researcher at Stanford University. "It's a low-frequency vibration in the ground."
"They just rumble for a while and stop, then rumble for a while and stop," said seismologist Robert Nadeau of the University of California at Berkeley.
Apr 20, 2006
Larry O'Hanlon
Discovery Channel
_____________
Mysterious rumblings detected inside and above the San Andreas Fault at Parkfield, Calif., have seismologists scrambling for answers, some of which might point to a new way to forecast earthquakes.
The unexplained rumblings are known by various names to seismologists, including "silent earthquakes," "slow slip events," "Episodic Tremor and Slip," or "non-volcanic tremors."
They don't jolt like earthquakes and seem to resemble the chaotic vibrations produced by a volcano's plumbing system, except that there's no live volcano anywhere near Parkfield.
"If you could listen to it, it'd be more like a tone, not a bang like an earthquake," said Paul Segall, a "silent earthquake" researcher at Stanford University. "It's a low-frequency vibration in the ground."
"They just rumble for a while and stop, then rumble for a while and stop," said seismologist Robert Nadeau of the University of California at Berkeley.
Apr 20, 2006
