by Michel Chossudovsky
from
PortlandIndiMedia Website
Mysterious tremors deep
beneath the San Andreas Fault near the quake-prone
town of Parkfield are shaking the earth's brittle crust, FAR
BELOW THE REGION WHERE EARTHQUAKES NORMALLY STRIKE -- and scientists
say THEY CAN'T UNDERSTAND WHAT'S HAPPENING or what the
motions mean. Seismic researchers are monitoring the strange
"vibrations"..."We see this kind of tremor activity inside volcanoes
like Mount St. Helens," Nadeau said,
"but that's due to
the movement of rising magma, and in the tremors we've recorded
there's NO EVIDENCE OF VOLCANISM and NO SEISMIC WAVES TYPICAL OF
ORDINARY EARTHQUAKES."
"In the US, the technology is being perfected under the
High-frequency Active Aural Research Program (HAARP)
as part of the ("Star Wars") Strategic Defence Initiative
(SDI). Recent scientific evidence suggests that
HAARP is fully operational and has the ability
of potentially triggering floods, droughts, hurricanes and
earthquakes. From a military standpoint, HAARP is a weapon of
mass destruction. Potentially, it constitutes an instrument of
conquest capable of selectively destabilizing agricultural and
ecological systems of entire regions."
Tremors rock earth
deep beneath San Andreas Fault
Puzzling vibrations
baffle researchers
by
David Perlman
Chronicle Science Editor
Friday, December 10, 2004
from
http://www.chron.com/cs/CDA/ssistory.mpl/headline/world/2941914
Mysterious tremors deep
beneath the San Andreas Fault near the quake-prone
town of Parkfield are shaking the earth's brittle
crust, far below the region where earthquakes normally strike -- and
scientists say they can't understand what's happening or what the
motions mean.
Seismic researchers are monitoring the strange vibrations closely.
But whether the faint underground tremors -- termed "chatter" by
some seismologists -- portend an increased likelihood of a major
quake in the area is an unsolved puzzle.
Robert Nadeau, a geophysicist at the UC Berkeley
Seismological Laboratory, has charted more than 110 of the faint
vibrations since they were first detected by the lab's High
Resolution Seismic Network in Parkfield three years ago. What
concerns Nadeau and his colleagues is that the epicenter of the
great 1857 Fort Tejon earthquake, whose magnitude has been
estimated at 7.8 to 8, was located almost exactly where the deep
tremors are now occurring -- beneath the San Luis Obispo County
village of Cholame, some 17 miles south of Parkfield.
The episodes of chatter last from four to 20 minutes and are being
recorded from as deep as 40 miles beneath the surface -- up to four
times the depth of normal earthquakes, which originate in what
scientists call the "seismogenic zone." That zone reaches no
deeper than 9 or 10 miles below the Earth's surface.
What's most striking is that deep tremors like the Cholame series
have never been recorded before on a strike-slip fault such as the
San Andreas, Nadeau said.
"We see this kind of
tremor activity inside volcanoes like Mount St. Helens,"
Nadeau said, "but that's due to the movement of rising
magma, and in the tremors we've recorded there's no evidence of
volcanism and no seismic waves typical of ordinary earthquakes."
Nadeau and
David Dolenc, a graduate student in his lab, are publishing the
first report on the mysterious sequence of deep tremors today in
Science Express, the online edition of the journal Science. They
conclude that,
"future increases in
San Andreas Fault tremor activity may signal
periods of increased probability for the next large
earthquake on the Cholame segment."
The Fort Tejon event
rocked the ground violently and ruptured the fault for 225 miles,
from northwest of Parkfield to San Bernardino.
It was at least as large as the 1906 San Francisco quake. But
because the Cholame region was virtually unpopulated at the
time, it killed only two people and destroyed only the Tejon Army
post, midway along the affected section of the fault.
The area is still sparsely populated; Cholame itself
boasts only 2,125 inhabitants. But Paso Robles, with a
population of more than 25,000, is only 25 miles west of the village
-- and it was badly damaged by a magnitude 6.5 quake only a year
ago.
Scientists have estimated that the Cholame segment of
the fault has ruptured in a large quake roughly every 140 years. It
is now 148 years since the Fort Tejon event, so the
possibility of another one may be steadily increasing, they say.
Similar deep tremors have been detected recently along the coast of
the Pacific Northwest, known as the Cascadia Subduction Zone,
as well as in Japan -- and there, too, scientists are
struggling to understand what their import is. In those areas, giant
slabs of the earth's crust are dipping downward and sliding
ponderously beneath other great crustal slabs, and scientists
believe that fluids -- most likely seabed water saturating the slabs
-- are causing the tremors, according to Herbert Dragert of
Canada's Geological Survey in British Columbia and
Kazushige Obara of Japan's National Research Institute for
Earth Science and Disaster Prevention.
In an interview, Dragert said the tremors appear to add
stress to a major thrust fault in the Puget Sound region, and
that scientists in Canada and Washington are trying to determine
whether the tremors might "play a significant role in triggering
great earthquakes."
In California, the most mystifying feature of the unexplained
tremors is that they are occurring right on the deepest part of the
San Andreas -- a fault that does not involve subduction or
volcanic activity. Instead, two sides of the earth's crust are
sliding horizontally past each other in a motion seismologists call
"right-lateral strike slip." In an earthquake, that slip can be an
abrupt jolt, and in big quakes, a violent one.
The tremors are occurring at such great depth, Nadeau said, that
they must be at the very bottom of the brittle crust -- where the
earth's hot, viscous upper mantle begins -- which has been under
stress for millions of years.
It's possible that the mantle there resembles something like Silly
Putty, Nadeau said, with great chunks of embedded rock
grinding against each other to generate [an area that is more prone
to the HAARP] tremor signals. That's purely a
speculation, Nadeau conceded, but so far it's the only one
around. [Tesla,
whose ideas are what originally led to such things like HAARP,
had ideas about sending energy waves through the mantle to transmit
them across the insides of the earth.]
"No one really knows
what the tremors mean," said David Schwartz, a
geophysicist at the U.S. Geological Survey in Menlo Park. "As to
what they imply for the possibility of some future quake, we
can't tell, and right now we can only wait and see."
A long-awaited
magnitude 6 quake struck Parkfield in September at a depth of
about 5 miles. That quake was seen as the latest in a series of
quakes that have hit around Parkfield on an average of
every 22 years between 1857 and 1966.
The Parkfield section of the San Andreas, in
southern Monterey County, is the most intensively instrumented
seismic danger region in the United States. A borehole 2 miles deep,
carrying an array of instruments and called the San Andreas
Fault Observatory at Depth, is to be
completed next summer.
Whether its instruments solve the mystery of the tremors and
determine whether they portend a future Cholame earthquake
remains to be seen.
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