Wednesday, March 16, 2011

For those who live on the North American West Coast we are entering a 'top seismic window' period (Updated)...

You should already be prepared for such a major earthquake here... but if you need an little incentive, watch this clip.

The premise is that recently there have been a series of strong earthquakes on the compression side of the pacific plate. We had the 6.3 in Christchurch, New Zealand last month, the huge 9.0 quake off the coast of north eastern Japan last week, the 8.8 quake in Chile on Feb 27 2010 (Nazca plate which contacts the pacific plate), the 8.1 Samoa earthquake on September 29, 2009.

I am no expert on earthquakes but it makes sense that when we get a series of major quakes around the edges of a major plate, it's likely that those quakes will alter the stresses at other regions of the plate.

Here's a map of the major plates with arrows indicating compression, slippage and expansion zones. (click on image to enlarge)

The Cascadia subduction zone can produce very large earthquakes ("megathrust earthquakes"), magnitude 9.0 or greater, if rupture occurs over its whole area. When the "locked" zone stores up energy for an earthquake, the "transition" zone, although somewhat plastic, can rupture.

Great Subduction Zone earthquakes are the largest earthquakes in the world, and can exceed magnitude 9.0.

Earthquake size is proportional to fault area, and the Cascadia Subduction Zone is a very long sloping fault that stretches from mid-Vancouver Island to Northern California. It separates the Juan de Fuca and North America plates. Because of the very large fault area, the Cascadia Subduction Zone could produce a very large earthquake.

Adding to all this is the fact that the last known great earthquake in the northwest was in January 1700, the Cascadia Earthquake.

Geological evidence indicates that great earthquakes may have occurred in the Cascadia region at least seven times in the last 3,500 years, suggesting a return time of 300 to 600 years.

In other words... it's been over 300 years and we can reasonably expect one anytime between now and 2300.

However, as noted on Wikipedia (See: Prediction of the next major earthquake), recent findings concluded the Cascadia subduction zone was more hazardous than previously suggested. The feared next major earthquake has some geologists predicting a 10% to 14% probability that the Cascadia Subduction Zone will produce an event of magnitude 9 or higher in the next 50 years, with the most recent studies suggest that this risk could be as high as 37%.

Geologists have also determined the Pacific Northwest is not prepared for such a colossal earthquake. The tsunami produced may reach heights of approximately 30 meters (100 ft), creating the same sort of devestation that has hit Japan.

[And just as scary, the Hanford Nuclear Plant in Washington State was built to withstand a 7.9 level earthquake... not a 9.0 quake]

If this wasn't enough, Geologist Jim Berkland outlines in the clip above that the months of October, March and April are the worst months for devestating earthquake damage.

On the 19th of March not only will we have the full moon, but within an hour of that we will have the closest approach of the Moon until the year 2016.

And the next day is the equinoctial tides.

So... (1) we are in the March/April period, (2) we have a full moon and (3) we have the closest approach of the Moon until the year 2016. This brings together three of the maximum tide raising forces.

In addition to this, when you combine the ocean tides with the earth tides and the tides in the ground water, all of these factors help to release sudden, built up strain and cause earthquakes.

Berkland calls this is a "top seismic window" which will develop between the week of March 19th to 26th.

Berkland also outlines a number of odd events with ocean wildlife that occured before previous earthquakes. Similar odd ocean wildlife events have occured on the West Coast recently.

It may be nothing, but it can't hurt to be prepared.

Pass the link to this post on to as many people as you know who live on the West Coast.



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Please read disclaimer at bottom of blog.


  1. For what it's worth, Hanford has been closed and has been in the process of being dismantled for many years...

  2. Thanks Bryn. It is important to note that Hanford still houses the Columbia Generating Station, a commercial nuclear power plant operated by Energy Northwest.

    It is a nuclear reactor and it provides Washington State with 9% of the state's electrical generation capacity. With the 1992 retirement of Oregon's Trojan Nuclear Power Plant, it is the only commercial nuclear power reactor remaining in the Pacific Northwest.

    In a recent TV interview, a spokesman re-iterated that the plant is built to withstand a 7.9 magnitude earthquake.

  3. Whisperer,

    I'm a big fan of your blog and follow it every day. Having said that, I'm extremely disappointed in this particular entry, specifically the inclusion of the pseudo-scientist and mystic, Jim Berkland.

    Berkland has made a great deal of hay from a single, moderately accurate prediction. However, one data point does not a scientific method make.

    Berkland's prediction methods are not connected to falsifiable hypotheses, and indeed rely partly on interpreting the behaviour of animals. One might as well view entrails as a source of data, or invoke oneiromancy.

    Like you, I am not a geologist or an expert in disaster preparation, but I too advocate preparedness for disaster and emergency. I lived in Japan and survived a major earthquake while there. It taught me that the earth will sometimes shake, so now I have food, water, essentials and a bug-out plan.

    But invoking someone as debunked and Berkman (see the Skeptic for a good drubbing of his nonsense) is a poor choice for informing your readers.

  4. Here, I just forced myself to look at his website. Here is his prediction for the 'June Window'

    (1) 3.5-6.5M within 2-degrees of Mt. Diablo (Lat 37.9N; Lon. 121.9W)

    (2) 3.5-6.5M within 2-degrees of Los Angeles (34.0N; 118.0W)

    (3) 3.5-6.5M with an epicentral address of Washington or Oregon.

    (4) 7.0+M major quake globally, most likely in the Pacific Ring of Fire.

    Oh for Chtulu's sake! How about I amaze the world with a prediction: I predict between 1 and four inches of rain somewhere in the lower mainland in the month of April.

    This is a perfect parallel: all of the areas mentioned by Berkman are in zones that already show frequent earthquake activity, and experience activity as low as 3.5M with high frequency. One doesn't feel them all because many are far below ground--yet by Berkman's methods this counts as a 'hit'.

    In addition, earthquake proximity is measured in a radius centered on the source of the activity. By quoting a box-shaped area encompassing two degrees of arc (each degree represents approximately 69 miles) Berkman gives himself not only a "hit" an event as much as 1.4 times farther than the radius would give, he's predicting inside an area of nearly 5,000 square miles, with no prediction for depth. Go down to the planet's core (allowed in his measurements), about 3,000 miles and you have a search area of 1.5 million cubic miles.

    So, I'm going to predict that somewhere above the Fraser Valley, between zero and sixty miles elevation, a cloud will appear between May 19th and May 21st. Will I get on the Art Bell show for my perspicacity?

    I could go on, but I have no scientific training, nor passion for dealing with custard-heads like Berkman.

    But I urge you to refute his data and inform your readers that panic based on Berkman's predictions are counter-productive.

  5. As I said, it may be nothing but it's worthwhile to be prepared.

    Panic, based on anyone's predictions, is not only counter-productive... but foolhardy.

  6. As an avid reader, I hope you choose to remove this post from it's headline status on your site. There is absolutely no correlation between the christchurch earthquake and the chile/japan quakes. I don't have time to comment further but this sensationalism is on par with wealthy asian renting helicopters to purchase White Rock condos.

  7. Thank you Whisperer for this post. I disagree that it should be removed. I think it's worthwile to be aware of this.