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This rendition of an OSU tsunami shelter prototype shows a large multi-story building on stilts, likely to lessen the impac of the base of a tidal wave crashing through its vicinity.  (Source: Oregon State University)
Shake, rattle, roll and splash -- major seismic event could ravage the pacific northwest twice over.

There have been no shortage of powerful and often, sometimes catastrophically, deadly earthquakes in the past ten years. Sumatra, Haiti, Japan, Chile and more have suffered to various degrees from the results of plate tectonics and the roiling seas of magma far below the surface of the planet. Though, in the US, California has a reputation for being earthquake-friendly, it is a far cry from the only threatened west coast state.

Based on data collected from the Cascadia Subduction Zone, which lies off the west cost of North America and runs from northern California up to British Columbia, Oregon State University marine geologist Chris Goldfinger and team says the chance of a quake of high magnitude, 8 or better, is unsettlingly high in the next fifty years. Using telltale signs of seismic activity, they have mapped out a time line of major events for the last 10,000 years. As it turns out, the pacific northwest is about due for a major earthquake.

According to their findings, the Cascadia has already gone past the 75% mark as far as a major event within a generally rhythmic period of time. Over the past 10,000 years, they have found evidence of 41 large events, spaced at roughly 500 year intervals. Should no event occur in the next 50 years, the chances jump to 85%. There is no doubt, feels Goldfinger, that the event is coming -- it's just a matter of time.

At present, he states there is an approximately 37% chance that a magnitude 8 or greater quake will hit the southern section of the Cascadia Subduction Zone, which runs from northern California to near Newport, Oregon, in the next 50 years. Further north, the chance of an event is less -- 10% to 15% -- but with a better chance of being much stronger, magnitude 9 or greater.

Not all of the west coast is oblivious to this sleeping giant. Not only would a sizable off-shore event cause the standard stand-in-a-doorway building rumbling action, it would most certainly create a powerful tsunami in its wake. The last recorded high magnitude quake from the Cascadia was in 1700. Though no records exist from the Americas, Japanese historians recorded the ocean-traversing tsunami that reached their shore, crashing down at 30 or more feet in height.

The town of Cannon Beach, Oregon, is working with engineers from OSU to create an earthquake and tsunami shelter for its residents using advanced construction techniques and an eye for vertical space to stand above the wave. If completed, it may be the first tsunami shelter built outside of Japan.



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RE: Bias? Fishiness?
By Iaiken on 5/25/2010 1:14:14 PM , Rating: 2
quote:
If you flip a hypothetical coin 10 times and each time ends up heads, your probability that the next flip is tails is extreamly high. Your chance of tails however is still 50/50.


Not entirely.

If you flip a coin 10 times and the previous 9 flips came up heads, your probability is the same as the previous 9 flips because the events are independent of each other. However, if you were you flip 10 coins simultaneously, the probability that all 10 come up heads is very low.


RE: Bias? Fishiness?
By Solandri on 5/26/2010 4:49:09 AM , Rating: 2
quote:
However, if you were you flip 10 coins simultaneously, the probability that all 10 come up heads is very low.

That's a subtly different problem. With the 9 coins flipped in sequence, the order matters. First you got 9 heads. Then you're asking what happens to the 10th flip.

If you flip 10 coins at once, then the order doesn't matter. You're saying any 9 of the 10 coins can be heads (rather than 9 specific pre-selected coins being heads). Then you're asking what's the chance of the 10th coin being heads.

Coin flip probabilities can get rather involved, especially with 10 flips. So the difference is best illustrated by a boy/girl example:
http://en.wikipedia.org/wiki/Boy_or_Girl_paradox


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