The 1,700-Foot Tusnami That Struck Alaska -Can It Happen Again?

On the night of July 7th, 1958, the world’s largest wave in recorded history engorged Alaska's Lituya bay, located about 250 miles west of Juneau in the Gulf of Alaska. It was 1,700 feet, or 520 meters -almost twice the height of the Eiffel Tower.

The tsunami was triggered by a magnitude 8.3 earthquake, which caused an enormous landslide along the Fairweather Fault. The resulting crash of rock into water caused the largest wall of water in human history. The deadly wave hurtled at jet speeds and wiped out everything within a four mile radius.

Fortunately Lituya Bay was virtually uninhabited, otherwise it would have caused unprecedented destruction, far greater than the tsunami that struck Thailand in 2004.

At the time of the colossal wave, there were only three fishing boats anchored out in the bay and amazingly only one sank, with two people losing their lives. The other boats were able to surf the crest of the tsunami.

The Science Channel and Dr George PC quoted one of the survivors Howard G. Ulrich in a recent article about the wave impact: Ulrich heard the sound of the enormous wave ripping through the land and obscuring the sky, he reportedly said to his 8-year-old child “Son…it’s time to pray.”

Can a similar tsunami strike the west coast of the U.S. again? Geological evidence makes it almost a certainty -the region is the heart of the world's most active sesmic zone: the Pacific Rim of Fire.

On January the 26th, 1700, sometime around 9 p.m. local time, the Juan de Fuca segment of the planet shifted -suddenly. It slipped some 60 feet eastward beneath the North American plate, and caused a monster magnitude 9 quake. It set in motion tsunamis that struck the coast of North America and traveled to the shores of Japan.

Seismic research shows that these mega quakes occur every 400 to 500 years.

Kim Olsen of San Diego State University (SDSU) and his team created a supercomputer-powered “virtual earthquake” program that allowed them to recreate such an event. This program encompassed the work of scientists from SDSU, San Diego Supercomputer Center at University of California/San Diego, and the U.S. Geological Survey.

To ensure that the entire representation of what could happen is accurate, William Stephenson of the U.S. Geological Survey worked with Olsen and Andreas Geisselmeyer from Ulm University in Germany to create an accurate representation of the earth’s subsurface layering that area. This “velocity model” – the first of its kind – expressed how the structure will bend, reflect, and change in size and direction.

Their scenario depicted a rupture beginning in the north and propagating toward the south along the 600-mile long Cascadia Subduction Zone (an area where two tectonic plates move towards one another, forcing one to slide beneath the other). In their scenario, the ground moved about 1.5 feet per second in Seattle, nearly 6 inches per second in Tacoma, Olympia and Vancouver, and 3 inches in Portland, Oregon.

“We also found that these high ground velocities were accompanied by significant low-frequency shaking, like what you feel in a roller coaster, that lasted as long as five minutes – and that’s a long time,” said Olsen.

“One thing these studies will hopefully do is to raise awareness of the possibility of mega-thrust earthquakes happening at any given time in the Pacific Northwest,” Olsen added. “Because these events will tend to occur several hundred kilometers from major cities, the study also implies that the region could benefit from an early warning system that can allow time for protective actions before the brunt of the shaking starts.”

This is bad news for the North West for two reasons: one, because the combined long-duration shaking and high ground velocities raise the possibility that such an earthquake could inflict major damage on downtown Seattle; and two, areas like Seattle, Tacoma and Olympia sit on top of sediment filled geological basins, thus, amplifying the waves generated by major earthquakes.

“The information from these simulations can also play a role in research into the hazards posed by large tsunamis," added Olsen, "which can originate from such mega-thrust earthquakes like the ones generated in the 2004 Sumatra-Andeman earthquake in Indonesia."

Posted by Casey Kazan with Josh Hill.

[Apologies, all: somehow we missed giving this post our usual copy-edit scrubbing when it was first posted at 12:15 this a.m.]

Related Galaxy links:

Tsunami-like Waves May Trigger Next Massive Yellowstone Explosion
The World's Most Massive Supervolcano: Yellowstone

Source:

http://www.environmentalgraffiti.com/offbeat-news/the-1700-feet-tsunami-that-struck-alaska/927

Comments

[bitirim]

thank you

sohbet siteleri sohbet sitesi sohbet odaları sohbet kanalları sohbet seviyeli sohbet

[yahoo music videos]

thankss

[Taylor]

Tee hee. "'Rim'" of fire". hoo boy.

[B]

So let me get this straight because I am a little skeptical.

A 1700 foot wave traveling at jet speeds and two boats surfed them.

Anyone else calling bullshit on this?

[M]

Let's be clear. The enormous wave was a function of the immediate geography, and limited to Lituya Bay. The land funneled the force of the water, causing it to be so extreme.

So while another earthquake could happen like that, and another landslide, it would still need other coincidental factors to get the same affect. It's not like something that would hit a major city in the Pacific NW.

[Casey Kazan]

Apologies, all: We just finished editing this post. Somehow, it missed getting our standard copy-edit scrubbing prior to posting at 12:15 this a.m. My thanks, Casey Kazan, editor.

[Frank Komitsky Jr]

Can you imagine the thrill of surfing a 1700 foot wave?

[Mike]

With regards to the boats "surfing" the 1700 foot wave - keep in mind that the wave reached 1700 ft in height when it hit the shoreline. Tsunamis are almost undetectable farther out - it's only when the wave hits the continental shelf that it really starts to rise up. Even then, it has to be in pretty shallow water to achieve its full height.

So while the boats may have indeed "surfed" the tsunami, I doubt it was anywhere near its full height at the time.

[Patrick]

Taylor, it's quite well-documented. See the over 7,000 references to the Lituya Bay tsunami at Google.

[Alex]

There was a very good show on discovery or the Science channel(I forget)discussing this tsunami. They also interviewed the people who survived and how they survived. Their boat rode the wave right up the mountain and right back down the mountain.
God must have been with them.

[two_ears_good]

tusnami? get that copy editor over here.

[Provillus]

Provillus natural hair loss treatment now available for Men and Women . Order here for your 90 Day Money Back Guarantee at www.Managehairloss.com