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95498 |
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Date: December 08, 2021 at 08:10:53
From: The Hierophant, [DNS_Address]
Subject: The OR swarm |
URL: https://www.msn.com/en-us/news/us/a-swarm-of-more-than-40-earthquakes-in-24-hours-is-causing-a-buzz-in-the-northwest-us/ar-AARBJ9t?ocid=mailsignout&li=BBnb7Kz |
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A swarm of more than 40 earthquakes in 24 hours is
causing a buzz in the northwest US
One of North America's most active fault lines sprung
to life on Tuesday after a swarm of more than 40
earthquakes -- ranging from a magnitude 3.5 to 5.8 --
rattled off the coast of Oregon, catching the attention
and concern of millions in the region.
The series of quakes, which began early Tuesday morning
and continued into Wednesday, were all clustered
between 200-250 miles west of the coastal town of
Newport, OR, far enough to be mostly undetected on
land, but given the area's seismic history, it is
creating quite a buzz.
"If you had asked me yesterday where on Earth would be
most likely to produce a bunch of magnitude 5.0+ quakes
in a single day, this would have been high on my list,"
Harold Tobin, Director of the Pacific Northwest Seismic
Network at the University of Washington, told CNN.
The fault line responsible for the quakes is the Blanco
Fracture Zone. According to an analysis by Oregon State
University, it is more active than the infamous San
Andreas Fault in California, having produced more than
1,500 quakes of magnitude 4.0 or greater since the
1970s.
Not all quakes are created equal
What has been most impressive about this week's quakes
is the swarm has included at least 9 tremors reaching a
magnitude 5.0 to 5.8, with the majority occurring at a
shallow depth of only 10 km.
The sheer number of magnitude 5.0 or greater quakes in
the region triples the annual average (three 5.0+
quakes per year) since 1980, according to the USGS
database.
Fortunately, according to the US National Tsunami
Warning Center, none of this week's quakes have
triggered a tsunami alert.
However, the activity has heightened the concern level
for some, as the region is among the most earthquake-
prone areas in North America and has already produced
one of the largest quakes in the continental United
States on January 26, 1700. The quake occurred on the
neighboring Cascadia Subduction Zone, a megathrust
fault much closer to land, where the Juan de Fuca plate
dives underneath the North American Plate. This fault
can not only trigger devastating tsunamis but also
destructive shaking.
This is not necessarily a precursor for the so-called
'big one'
Though the epicenter of this week's swarm of quakes,
the Blanco Fracture Zone, is among the most seismically
active in North America, it rarely leads to destructive
quakes.
The fault is some 275 miles west of the Oregon
coastline and about 200 miles west of the Cascadia
Subduction Zone, where the largest and most destructive
Northwest quakes have historically taken place.
"Blanco Fracture zone quakes are strike-slip (lateral
motions of the crustal blocks on either side, rather
than up-down displacement), so it is very unlikely for
them to pose a tsunami threat, even if a bigger quake
happened, like a magnitude 7.0 for example," Tobin told
CNN.
According to seismologist Dr. Lucy Jones, there have
been more than 133 quakes of magnitude 5 or greater on
the Blanco Fracture Zone since 1980 and have never been
followed by something on land.
"Today's quakes can be thought of as something like a
main-shock and a swarm of aftershocks, the one
distinction being that in this case, there's not a lot
of magnitude difference among them," Tobin said.
Though this week's quakes have raised the concerns the
so-called "big one" could be near, Tobin assured it is
not necessarily the case.
"There's quite a lot of distance from these quakes to
the Cascadia Subduction Zone," Tobin explained. "Our
best current understanding of how stress transfers
through the crust (and mantle) would suggest that these
events don't change stress on the subduction zone
appreciably."
He pointed out, although we have had a remarkable
number of magnitude 5.5+ quakes in a short period of
time, it is not inherently alarming but rather
seismologically interesting.
A similar swarm of quakes, though not to this week's
magnitude, occurred earlier this year near the Salton
Sea in Southern California.
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[95501] [95502] [95503] [95504] [95507] [95506] |
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95501 |
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Date: December 08, 2021 at 11:31:57
From: kay.so.or, [DNS_Address]
Subject: Re: The OR swarm |
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when they had the 6.8 off the coast a few years back, my house in O'brien (at the time) which is an hour away from the coast, started my bling rattling on my windows to begin with and I said huh-oh, quake and then the whole house got hit with a big BAM, shook real good. Its really telling us how mother earth's geography is connected, probably in ways that the scientists don't even understand yet. this house does a creak or crack at times and there are splits outside that I know are from picking up waves from ground movement. I took an earthquake class at Humboldt in arcata years ago, was so educational. we even got to see the drum that recorded them and was interesting that even the waves of the ocean hitting the shore showed up on the seismograph.
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[95502] [95503] [95504] [95507] [95506] |
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95502 |
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Date: December 08, 2021 at 15:31:33
From: Barb sw wa, [DNS_Address]
Subject: Re: The OR swarm |
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My apartment walls have been creaking, too! And am
noticing the windows'"sounds" that make me think they
are about to break! My headaches are like the eq
headache symptom I have had in the past for the N. CA
region, or thereabouts. Any headaches/queasy stomach
for you during this swarm?
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95503 |
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Date: December 08, 2021 at 18:54:34
From: kay.so.or, [DNS_Address]
Subject: Re: The OR swarm |
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yes on the headaches barb, also left shoulder/collar bone real painful, tum is 'off' but not sure its 'momma' related as I have 'stuff' going on so that is a ???I posted on earth groans, spike n bottom left heel
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95504 |
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Date: December 08, 2021 at 20:42:37
From: Barb sw wa, [DNS_Address]
Subject: Re: The OR swarm |
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Kay, the bottom of the heel was the biggest symptom I
had before the Nisqually 6.8 quake! ...I had it at
least three weeks prior to that quake and it
disappeared once the quake happened... My stomach is
so off that I feel I'd just be better to not eat
anything all for at least two days. ...Oh, sure... :))
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[95507] [95506] |
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95507 |
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Date: December 08, 2021 at 21:02:05
From: kay.so.or, [DNS_Address]
Subject: Re: The OR swarm |
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just researched it and it was 20 years ago today, and she is driving there tomorrow and getting off at that exit...told her 'heads up girl'!....
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95506 |
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Date: December 08, 2021 at 20:55:01
From: kay.so.or, [DNS_Address]
Subject: Re: The OR swarm |
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oh wow ...have to warn my washington friends now!..glad you told me barb...hmmmm
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