Mega-earthquake Risk For West Coast, US And Canada?

Seismic Slip Linked To Tremor, With Implications For Subduction Zone

ScienceDaily (Feb. 2, 2009) — In the last decade, scientists have recorded regular episodes of tectonic plates slowly, quietly slipping past each other in western Washington and British Columbia over periods of two weeks or more, releasing as much energy as a magnitude 6 earthquake.

The slip events coincide with regular occurrences of what scientists call nonvolcanic tremor, which showed up clearly on seismometers but for which the origins were uncertain.

Now researchers from Italy and the University of Washington have concluded that both phenomena are signs of the same processes taking place about 25 miles deep at what is believed to be the interface between the Juan de Fuca and North American tectonic plates.

"We are now more confident that the tremor and the slip are both products of the same slip process," said Kenneth Creager, a UW professor of Earth and space sciences and a co-author of a paper describing the research being published Jan. 30 in Science.

The findings could have major implications for megathrust earthquakes in the Cascadia subduction zone, an area along the West Coast from northern California to southern British Columbia. Megathrust events are huge earthquakes, often in the range of magnitude 9, that occur in areas where one tectonic plate is forced beneath another.

The slow slip events appear to be building stress on the megathrust fault, where the Juan de Fuca plate is sliding beneath the North American plate, with the two locked together most of the time. That pressure is relieved when the plates slip during megathrust earthquakes such as one determined to have occurred off the coast of Washington on Jan. 26, 1700, estimated at magnitude 9.2. That quake was similar to the great Sumatra-Andaman Islands earthquake the day after Christmas in 2004, which also measured 9.2 and triggered a devastating Indian Ocean tsunami.

In such events, the plates are locked together for hundreds of years and then slip past each other by sliding 50 feet or more during a megathrust earthquake.

www.sciencedaily.com...



In reading this, I can't help but immediately think what the possible implications of this could be for Yellowstone. We witnessed the huge waves from a 7+ magnitude quake thousands of miles away shake the earth and show up on seismographs at Yellowstone.

Something this big, as in a magnitude 9+, that close to Yellowstone could have dire consequences for the supervolcano. Then again, Yellowstone may handle it well, with no critical magma chamber caps being affected.

The consequences of such a quake are bad enough for this region, and could kill thousands of people. But if it dislodges critical structures in Yellowstone as well, we could be facing a catastrophe of epic proportions.

This is a really scary thought, cali slips into the sea and a wave crashes across the ocean while at the same time a supervolcano bursts in yellowstone!

I wonder if the elite know its coming are have taken all their money put of cali? doubt itbut i do love the3 doomm

reply to post by NatureBoy


Actually I don't think Cali will slide into the Ocean...it's being pushed North & East by the Pacific & Coco Plates...but it COULD gain/lose 20 to 50 Ft in altitude REAL FAST along San Andreas or Garlock Fault Zones...

Washington state Seattle area.
This brings me to two days ago. I was at work and noticed water bubbling up from the ground. It seemed as though 100 gallons started gushing out of two small holes in the ground then 3 minutes later it stopped. It freaked me out because it has not rained in over a week. First thought that came to mind was the plates moving below my feet. I have a gut feeling something is going to happen pretty quick.

reply to post by wiredamerican


Was it in a populated area with public water utilitys? Could of been a Water Main/Sewer/Drainage leak/break from recent Eq Activity...

[edit on 2/5/2009 by Hx3_1963]

reply to post by NatureBoy


The seed bank sure raised a lot of eyebrows. Why would they do something like that unless they expected a major catastrophe? Preemption. All the rage these days. Doesn't hurt to be prepared.