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8.9 Earthquake hits Japan

 
 
Reply Fri 11 Mar, 2011 07:05 am
I'm just hearing about this. If it's really an 8.9, that's huge. The tsunami's look devastating going through the Japanese fields/towns.

They are reporting the death toll at 60 people currently, that seems ridiculously low to me. From what I can see on the videos this thing looks horrible.

Hopefully the construction standards in the major cities will moderate some of the damage.

Hopeful thoughts and best wishes for the people of Japan and people along the affected coasts.
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Type: Discussion • Score: 5 • Views: 2,760 • Replies: 17
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rosborne979
 
  1  
Reply Fri 11 Mar, 2011 07:34 am
@rosborne979,
Oops, I just found the other thread on this: http://able2know.org/topic/169093-1#top
0 Replies
 
Sglass
 
  1  
Reply Fri 11 Mar, 2011 09:19 am
@rosborne979,
retro fitting is in process in Hawaii.

local radio said the Tsum. has reached Tawain and the increase in wave size is maybe 4 inches.

Wakiki Beach was evacuated, but again the Tsum. is not causing major flooding.

What concerns me is that I am aware there is a major shelf off the coast of Japan and if the aftershooks cause it to collaspe it would generate waves a mile high.

might not be out of the woods.
rosborne979
 
  1  
Reply Fri 11 Mar, 2011 12:12 pm
@Sglass,
Sglass wrote:
What concerns me is that I am aware there is a major shelf off the coast of Japan and if the aftershooks cause it to collaspe it would generate waves a mile high.

I don't think the "shelf" off the coast of Japan is like a closet shelf with nothing underneath it. It just refers to a sharp drop-off in sea floor elevation. So I don't think it's any more likely to "collapse" than to have another earthquake happen.
Butrflynet
 
  0  
Reply Fri 11 Mar, 2011 01:54 pm
@rosborne979,
Here's an interesting pdf presentation about undersea landslides and the tsunamis they can generate:



Proceedings of The Thirteenth (2003) International Offshore and Polar Engineering Conference
Honolulu, Hawaii, USA, May 25–30, 2003
Copyright © 2003 by The International Society of Offshore and Polar Engineers
ISBN 1–880653-60–5 (Set); ISSN 1098–6189 (Set)

Underwater Landslide Shape, Motion, Deformation, and Tsunami Generation


And an article about such an event off of PNG in 1998:

http://articles.sfgate.com/2000-12-19/news/17673871_1_major-earthquakes-landslides-tsunami
realjohnboy
 
  1  
Reply Fri 11 Mar, 2011 08:39 pm
@Butrflynet,
There are 2 threads about this. I am going with the latter.
The nuke plants thing looks like it could be serious.
Butrflynet
 
  0  
Reply Fri 11 Mar, 2011 09:01 pm
@realjohnboy,
I posted that here because the discussion about undersea landslides was here. It is a concern for both coasts of the US and we should probably start taking it more seriously.

Maybe I should just start a separate topic for it... hmm
realjohnboy
 
  2  
Reply Fri 11 Mar, 2011 09:14 pm
@Butrflynet,
You and failure art started threads. Neither has gotten much attention on A2K. The nuke power plants has gotten my attention.
Butrflynet
 
  2  
Reply Fri 11 Mar, 2011 09:19 pm
@realjohnboy,
I haven't started any threads on the Japan quake. This one was started by Rosborne.

I've been posting on Cycloptichorn's thread for nearly 24 hours now. That's where I posted the info about the nuclear emergency.

Here's a link to the thread if you need it:

http://able2know.org/topic/169093-1

Please join us there.
0 Replies
 
Sglass
 
  1  
Reply Fri 11 Mar, 2011 10:52 pm
Sorry Roz, I said shelf. I really meant larsen ledge which is about the size of the state of Texas
Sglass
 
  1  
Reply Sat 12 Mar, 2011 07:54 pm
@Sglass,
Oh, just got back from Volcano whereas I had a conversation with a gentleman from Japan and he said the eathquake has put a crack in the ledge. Now the ledge was not supposed to let go for another 500 years and do mile high tsunami waves. But now, who knows.
0 Replies
 
Butrflynet
 
  1  
Reply Sat 12 Mar, 2011 08:00 pm
@Sglass,
Is that the Larsen's ledge ice sheet that is in Antarctica?

http://en.wikipedia.org/wiki/Larsen_Ice_Shelf


If there is a crack in it, I doubt it is from the earthquake in Japan... more likely Christchurch's quake last September.
0 Replies
 
Butrflynet
 
  1  
Reply Sat 12 Mar, 2011 09:10 pm
Interesting article here about undersea landslides:

http://www3.ncc.edu/faculty/bio/fanellis/biosci119/tsunami_caused_by_slides.html

A few excerpts:

Quote:
April 23, 2002

A microphone in the Pacific Ocean near Wake Island recorded a 45-second, low-frequency roar, too low to be heard by human ears. It was the sound of nearly a cubic mile of sediment giving way along an ocean bottom slope 2,200 miles away off Papua New Guinea.

That recently examined recording is the latest evidence that an underwater landslide, not an earthquake, churned up the 30-foot-high tsunami that crashed onto coastal villages of Papua New Guinea on July 17, 1998, killing more than 2,100 people.

Once thought rare, landslide-generated tsunamis have caught the attention of geologists, who now look with concern at other continental shelves that could collapse with equal disaster. Three-dimensional maps of the bottom of Monterey Bay off California, for example, show several sections that have given way - and others that have cracked and may collapse in the future.

...

Small landslides - or ones that slip slowly - do not cause tsunamis. Cataclysmic landslides, like the partial collapse of a midocean volcano, generate giant waves that scour thousands of miles of coastline around an entire ocean basin, but they occur very rarely, once every few hundred thousand years.

But moderate-size underwater landslides like the one off Papua New Guinea may pose an uneasily plausible risk in some places, occurring once every few hundred years.

"It is a reasonably significant hazard," said Dr. Emile A. Okal, a professor of geological sciences at Northwestern University in Evanston, Ill.

Almost immediately after it happened, scientists realized the Papua New Guinea tsunami was unusual. An offshore earthquake of magnitude 7.0 preceded the waves, but earthquakes that size strike that area every year or two; only the 1998 one was accompanied by a tsunami. The deadly devastation was also confined to a 15-mile stretch of the coast; villages only a few miles east or west escaped almost unscathed.

That led to speculation that the earthquake had shaken loose a landslide that in turn caused the tsunami. Surveys of the ocean bottom found freshly collapsed sediment that slid nearly a mile down a 25-degree slope.

Other scientists argued that a vertical thrust of the sea floor during the earthquake directly caused the tsunami, but that the amphitheater-shaped depression around the epicenter focused the waves onto the small section of the shoreline.

...

The theory that underwater landslides can set off tsunamis dates back more than a century. In recent decades, tsunami researchers shifted their attention to offshore earthquakes, still thought to be the cause of most tsunamis.

But after Papua New Guinea, scientists thought they might have underestimated the dangers of landslides. In 2000, scientists at Pennsylvania State University warned of unstable, waterlogged sediments under the seabed off New Jersey. The weight of rocks above could potentially blow the sediments out the side of the continental slope like a stepped-on water balloon, causing a landslide and a tsunami.

Scientists also see potential collapses in places like the mouth of the St. Lawrence River where sediment from the river piles up. In 1929, a 7.2 earthquake toppled part of the sediment pile, causing a tsunami.

Underwater landslides have also occurred off the coast of California. In Monterey Bay, "you see large numbers of bites taken out of the canyon essentially," said Dr. Steven N. Ward, a research geophysicist at the University of California at Santa Cruz. "Some look very fresh. Some look very old. Some look like they haven't happened yet."

The canyon is cracked in some places, Dr. Ward said, and even a small earthquake near a crack could set off a landslide. Most of the slides in Monterey Bay are small - only about a fortieth the volume of the Papua New Guinea landslide - but because they occur very close to shore, they could still create 15- to 20-foot-high waves that strike a small portion of the coast. "Ten miles up or down the coast, you won't see it," he said. "It's big, but it's fairly local."


And another article on the same page:

Quote:
Fissures off Va. Coast May Presage Tsunami, Experts Say

Wednesday, May 3, 2000

Researchers setting out to sea from the Virginia coast hope to find answers to a new scientific riddle: Could tsunamis, the large, destructive waves that have terrorized Japan and the rest of the Pacific for centuries, pose a threat to the mid-Atlantic coast as well?

According to the latest research, they might. Scientists have discovered a 25-mile series of cracks along the edge of the continental shelf, about 100 miles east of Virginia Beach and the mouth of the Chesapeake Bay.

If the fissures are moving, they could be the beginning of the type of underwater landslides that trigger tsunamis, according to a report just published in the May issue of Geology magazine.

Scientists estimate that a landslide from the fissures could send a wave 20 feet high hurtling up the region's beaches. Such a wave hitting southern Virginia would be similar to the force of a severe hurricane. In 1972, Hurricane Agnes caused the worst flooding the Washington area had seen in decades; it washed out roads and bridges and killed 118 people from Florida to New York.

...

Yet even on North America's Atlantic coast, tsunamis are not unprecedented. In 1929, a wave measured at up to 40 feet slammed into the southern coast of Newfoundland, killing 51 people. The landslide in that case was about the same size as the one that researchers fear could happen off the Virginia coast.

...

Driscoll, Weissel and colleague John A. Goff, of the University of Texas, plan to set out to sea Saturday for two weeks to get a closer look at the potential landslide area. The researchers will use special sonar equipment to determine how recently the cracks opened and, perhaps, predict how soon a tsunami could occur.

The Geology article stresses that "it is unclear whether these cracks are fossil features or are active and therefore likely to produce a potentially large submarine landslide in the near future." Driscoll and Weissel said that if their examination shows that the cracks are recent, they will install monitoring equipment to see whether they are moving.

Driscoll said the cracks were not the only thing that caught researchers' attention: The fissures are just north of an Ice Age landslide that occurred about 18,000 years ago--which is not all that long in geologic terms. "If it was just the cracks themselves, that might be different," Driscoll said. "But this has happened before in this area."



Sglass
 
  1  
Reply Sun 13 Mar, 2011 06:11 am
@Butrflynet,
Thank you for pointing out my lack of correct information.

So is the trough the Okinowan Trench?
0 Replies
 
LionTamerX
 
  2  
Reply Sun 13 Mar, 2011 07:29 am
Some pretty amazing images and before and after shots of the devastation. The last three images are of the area where a family member of mine lives. (He's safe.)

http://www.abc.net.au/news/events/japan-quake-2011/beforeafter.htm
Butrflynet
 
  1  
Reply Sun 13 Mar, 2011 01:02 pm
@LionTamerX,
Glad to hear he is safe. Those before and afters leave me speechless. Very much like the aftermath of the Indonesian tsunami.
0 Replies
 
JPB
 
  1  
Reply Sun 13 Mar, 2011 04:26 pm
Another "after" pic. I have no words beyond thoughts and prayers to all who were there at the time.

http://msnbcmedia2.msn.com/j/MSNBC/Components/Slideshows/_production/ss-Japan-Quake-tabbed/Day3_ss-110312-japanquake/ss-110313-quakekc-05.grid-5x2.jpg
0 Replies
 
Sglass
 
  1  
Reply Mon 14 Mar, 2011 08:51 pm
@LionTamerX,
You mean there are Latvians in Japan?
0 Replies
 
 

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