Posted on 04/19/2011 9:48:29 PM PDT by george76
The scale of Japan's March 11 earthquake and tsunami wasn't the only thing that surprised geologists.
The 9.0 earthquake in Japan — the fourth most powerful quake ever recorded — also caused an unusually severe and widespread shift in soil through liquefaction, a new study suggests.
Near coastlines, harbors and rivers, earthquakes can make the wet, sandy soil jiggle, turning it temporarily from a solid to a liquid state, a process known as liquefaction. Heavy sand and rock sinks, while water and lighter sand bubble to the surface. The slurry spreads, often toward the water, and the surface shifts.
Japan's liquefaction occurred over hundreds of miles, surprising even experienced engineers who are accustomed to seeing disaster sites, including from the recent earthquakes in Chile and New Zealand.
The study raises questions about whether existing building codes in other vulnerable locations can enable structures to withstand massive liquefaction, including in areas of Oregon, Washington and California.
...
About 1,100 bridges in Oregon are at risk from an earthquake on the Cascadia Subduction Zone, according to the Oregon Department of Transportation. Fewer than 15 percent of them have been retrofitted to prevent collapse.
(Excerpt) Read more at news.yahoo.com ...
ping
No joke. 9.0’s don’t happen every day of the week.
Thank God for that.
Upon this rock...
If memory serves, the most liquefaction observed so far in a North American event was with the great New Madrid earthquakes.
liquifaction is some scarey stuff - and hundreds of miles? just wow but it would explain why houses and businesses just floated off their foundations with what seemed was very little resistance to the tsunami
I’m curious how much of Japan’s coastline not only liquifacted but permanently sank and if more sinking is happening There are a couple of faultlines at work I think.
If a 9.0+ hits, I am willing to bet 90% of the bridges will fall no matter how much moola you spend on reinforcing.
The other 10% will require lots a repair before they are usable again.
fyi
Is it just the writers or are too many scientists brains locked into a textbook phase. Everything that I think would be a normal result of something turns up in the news as a bizarre phenomenon, or surprisingly inconsistent with past history. Liquefaction is the spontaneous result of earthquakes and water. The longer the earthquake and the more water, the more severe liquefaction will result.
I do hope there is some method which can aid book bound scientists experience the full mental functionality of asking themselves the question “what if” and at least having an idea of the result so they aren’t continually shocked.
It makes the Fukushima reactor site all that much more an engineering miracle than it already was.
Withstood a 9.0 quake, the liquifaction, then a tsunami that struck with less than 15 minutes warning.
The only failure in all of this was plant personnel and not updating some of the equipment.
I’m amazed.
I agree. At that point, you are going to have issues.
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You obviously missed the hydrogen explosions and the resulting severe damage to concrete structural beams and concrete fuel storage pools that occurred in reactor structures 3 & 4.
It appears that the concrete was of inferior quality. Prior earthquake damage may have exacerbated the failures, but the spalling and "cracking and racking" observable in those concrete beams should not have occurred with a low VOD H2 explosion.
You have a good point. Liquefaction is probably the cause of quicksands, which have been known and feared for centuries.
Shaking is not the only thing that can cause liquefaction, gases (e.g., methane) rising to the surface will do it, too [see ‘fluidized bed’]. I wonder how much of the Japan liquefaction is due to underground gases being released by the shaking, rather than the shaking directly.
I have seen an underground water supply rise from below 300’ to less than 50’ over thirty years. Now three miles away at another well, the water remained at about 200-240 feet all year long, the entire thirty years. I suspected it was the result of tiny earthquakes in the area.
When I mentioned this to a well driller he said it was common to see steady water level fluctuations in some parts of the county. He had an old water level map his dad started. He said by studying it you could see there was an underground river (large water flow) that crossed the county and it had changed its depth and location in places by a few miles over the past sixty years.
Nothing remains the same.
That island MOVED 24 meters ....80' ... to the SE. The Tsunami that hit Fukushima was 50' ....14.5m .... high!
And in the next five years as the island settles into a solid resting spot, it’ll probably shift another 20 to 50 feet feet. The shaker moved billions of tons of soil and it isn’t settled as of this short timespan.
The 9.0 earthquake in Japan -- the fourth most powerful quake ever recorded - also caused an unusually severe and widespread shift in soil through liquefaction
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