Be concerned!: Seismic changes along the Cascadian Subduction Zone

(News & Editorial/ Be concerned!: Seismic changes along the Cascadian Subduction Zone)

A.  (UPDATE) Imminent Magnitude 9 Earthquake?
8 November 2012, Modern Survival Blog, Submitted by Ken
Pasted from: http://modernsurvivalblog.com/

Earthquakes trigger more earthquakes.

UPDATE: Magnitude 6.3 NOV-8 Earthquake At Cascadia Raises More Concern
At the Seismology Lab at the University of Washington, there is concern that the 7.7 magnitude earthquake that occurred on the British Columbia coast over the weekend could affect the Pacific Northwest including Washington, Oregon, and northern California.
“We need to watch the whole region with extra care,” said a seismologist there.

The magnitude 7.7 was a big earthquake, considered one of the most significant along the northwest coast in 60 years.

Reported by NWCN.com in Seattle, scientists also looked to see if the quake affected volcanoes in Washington, and will remain on alert for at least several more weeks. So far, everything is quiet…

The problem is that the West Coast, from Alaska to northern California, is under tremendous geologic pressure as it’s forced up against the basin that forms the Pacific Ocean.

Release the pressure in a major way along one fault, and it can then add to the pressure on another fault. More than 100 aftershocks were recorded following the 7.7, including one of them more than 100 miles south of the quake’s epicenter, thought to be on the Cascadia Subduction zone.

The subduction zone threatens a much larger quake…
a magnitude
9
from the northern tip of Vancouver Island to Cape Mendicino California.

Such an earthquake would be devastatingly catastrophic, particularly to Seattle, Portland, and all of the cities and towns that run up and down the west coast, even through mid California.

I’m posting this as an alert that something ‘could’ happen as a result of this recent aftershock earthquake, which is well south of the main quake on the Cascadia Subduction zone… this looks potentially ominous.

If you live in or near those regions, examine your existing supplies, food, water, bug-out capabilities. Make a plan. Be ready. Just in case…

UPDATE: It is now being reported that the centuries old and famous “Haida Gwaii” Hot Springs in the region of the 7.7 earthquake… has dried up and gone cold.

A Parks Canada inspection party set out to investigate and stepped ashore to find that the island’s three main hot spring pools, which once bubbled with water as warm as 77 Celsius, were bone dry. “Not even a small puddle,” Surrounding rocks, once warm to the touch, were cold.

source: http://news.nationalpost.com/2012/11/02/bc-earthquake-hotspring/

(This is obviously IMO related to the recent B.C. earthquake, and further indicates the great unseen changes that have taken place as a result.)

NOV-8, 6.3 Quake at Cascadia Subduction Zone Raises More Concern

Since the large magnitude 7.7 earthquake of OCT-28, not only have hundreds of aftershocks occurred in the immediate vicinity, but other curious earthquakes have been triggered further south, within the Cascadia subduction zone. On NOV-8 an especially large earthquake shook that region, further indicating that stresses have transferred into that region. Why is this significant? Because the Cascadia fault is EXTREMELY DANGEROUS for the entire Pacific Northwest.

The Cascadia subduction zone (Cascadia fault) is a type of tectonic plate boundary that stretches from northern Vancouver Island to northern California. It is a very long sloping fault that separates the ‘Juan de Fuca’ and North America plates.

Ocean floor is sinking below the continental plate offshore of Washington and Oregon. The North American Plate is moving southwest, riding over the top of the oceanic plate. The Cascadia Subduction Zone is where the two plates meet. Unlike other faults that slide along side each other, this one is particularly dangerous because one plate rides over the top of another.
[Photo: Portland, Oregon and Mt. Hood – volcano]

To make matters worse, the Cascadia fault intersects and transitions with other faults at it’s north and south boundaries, including the infamous San Andreas fault which runs down the length of California. Studies of past earthquakes on both the northern San Andreas Fault and the southern Cascadia subduction zone indicate that quakes on the Cascadia subduction zone may have triggered most of the major quakes on the northern San Andreas during at least the past 3,000 years, with the exception being the great 1906 San Francisco earthquake.

The next rupture of the Cascadia Subduction Zone is anticipated to be capable of causing a magnitude 9+ earthquake and widespread destruction throughout the Pacific Northwest. And in fact, evidence suggests that a major Cascadia earthquake will likely rupture the San Andreas fault as it splits down into California, the combined effects of which would be more than devastating.

Geologists and civil engineers have broadly determined that the Pacific Northwest region is not well prepared for such a colossal earthquake. The tsunami produced may reach heights of approximately 100 ft. The earthquake is expected to be similar to the 2011 Tōhoku earthquake and tsunami, as the rupture is expected to be as long as the 2004 Indian Ocean earthquake and tsunami.

Left: Cascadia Subduction Zone
Right: Earthquakes since the OCT-28 quake (until this update)
Note the significant recent quakes south of the initial quake (the top cluster)

.

B.  Growing tension along Cascadia subduction zone: Washington rattled by series of tremors
15 October 2011, by The Extinction Protocol
Pasted from: <http://theextinctionprotocol.wordpress.com/2011/10/15/growing-tension-along-cascadia-subduction-zone-washington-rattled-by-series-of-tremors/        

   

October 15, 2011 SEATTLE – Washington has been hit by three earthquakes in four hours. Two of the quakes were in the 3.4 magnitudes and very shallow- ranging in depth from 8.5 to 1.4 km. There was also a 2.9 magnitude earthquake, less than 1 km in depth, near Mt. Rainer. Mount Rainier is a massive stratovolcano located 54 miles (87 km) southeast of Seattle in the state of Washington, United States. It is the most topographically prominent mountain in the contiguous United States and consequently the Cascade Volcanic Arc, with a summit elevation of 14,411 feet (4,392 m). Mt. Rainier is considered one of the most dangerous volcanoes in the world, and it is on the Decade Volcano list of potentially catastrophic volcanoes that could erupt with very deadly consequences. Because of its large amount of glacial ice, Mt. Rainier could potentially produce massive lahars that would threaten the whole Puyallup River valley. The last eruption of Mt. Rainer occurred in 1894. Recently, the icy summit has been stirred by tremors which again portends the fact that the northwest quadrant of the U.S. is becoming more geologically active. On September 9th, a 6.4 magnitude earthquake struck off the coast of Vancouver Island and recently, a 5.3 earthquake struck the off the coast of Oregon on October 13, 2011. On April 6, a massive undersea eruption occurred and was later discovered by Oregon State University geologist Bill Chadwick in August. The eruption produced a lava flow 1.2 miles wide. Also in September of this year, scientists discovered a 32.2 km (20 mile) long fault under Mt Hood in Oregon that was capable of generating a magnitude 6 or 7 earthquake. Scientists believe a 9.0 earthquake is long overdue for the Cascadia Subduction Zone of the Northwest but ultimately, the geological change potentially facing the region could be something even more dramatic. In 2009, New Zealand geologists discovered preliminary evidence which suggested the volcanic mountains of Washington might all be linked by a common magma pool. (See diagram below).The almost linear volley of volcanoes strewn across the northwest U.S. corridor from Northern California to Washington, may suggest the entire region could be susceptible to cascading fissure tear eruptions from the strait of San Juan de Fuca to northern California if the entire region was thrown into upheaval from a series of major earthquakes. Admittedly, this is a worst-case scenario that could only be triggered by a string of very large continuous earthquakes and such a catastrophe may never happen but it does highlight some of the potential dangers of the underlying hazardous faults and volcanic systems buried in the region.

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