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Posted on 07/26/2007 1:42:31 PM PDT by blam
Major Quake Likely in Middle East, Survey Finds
Kate Ravilious
for National Geographic News
July 26, 2007
In A.D. 551, a massive earthquake devastated the coast of Phoenicia, now Lebanon. The disaster is well-documented, but scientists had struggled over the years to locate the earthquake fault.
Now a new underwater survey has uncovered the fault and shown that it moves approximately every 1,500 years—which means a disaster is due any day now.
"It is just a matter of time before a destructive tsunami hits this region again," said Iain Stewart, an earthquake expert at the University of Plymouth in the United Kingdom not involved in the underwater survey.
Hitting the Jackpot
Earthquakes are common in Lebanon, but many of the faults remain unidentified, hidden beneath the deep waters of the Mediterranean Sea.
Surveying this region is difficult because some of the continental shelf drops off very quickly, reaching water depths of around 4,921 feet (1,500 meters) only five miles (eight kilometers) from the shore. (See a Lebanon map.)
Ata Elias of the National Center for Geophysical Research in Beirut, Lebanon, and his colleagues had a hunch that the fault responsible for the A.D. 551 earthquake would lie in this offshore region, so they did an underwater geophysical survey—and "hit the jackpot," Elias said.
By bouncing radio waves off the seafloor and studying the reflection patterns, Elias and his team were able to build a three-dimensional map showing all the lumps and bumps on the seafloor.
Running parallel to the Middle Eastern coast, they discovered a distinctive stepped ridge—the shape made by a "thrust" fault when one of Earth's tectonic plates shoves its way underneath another.
"We inferred that this thrust fault is the source of major earthquakes," Elias said.
The team was able to trace this fault along the coast for more than 62 miles (a hundred kilometers).
The findings are published in the August issue of the journal Geology.
Shell Secrets
Back on land the team found additional evidence to link this fault to the A.D. 551 earthquake. A "staircase" of platforms rising from present-day sea level showed how the land had moved upwards each time the thrust fault moved.
Enlarge Photo
When the thrust fault ruptured it uplifted the coastline by around three feet (one meter), Elias said.
When the platforms were at sea level they were colonized by mollusks. But as soon as they were thrust out of the water by the earthquake the mollusks died.
By dating the mollusk shells on the raised platforms, Elias and his colleagues determined when the thrust fault moved.
At least four earthquakes similar to the A.D. 551 quake have occurred over the last six to seven thousand years, the team found—suggesting a 1,500- to 1,750-year recurrence time for destructive quakes.
From the length of the thrust fault and the amount of uplift of the platforms on land, Elias and his colleagues estimate that the A.D. 551 earthquake must have had a magnitude of about 7.5 on the Moment magnitude scale, a more modern form of measurement than the Richter scale. (What is an earthquake?.)
When the fault ruptured in A.D. 551, part of the the seafloor block collapsed by around 5 to 10 feet (1.5 to 3 meters). This vertical drop in the water triggered a surging tsunami, which gained height rapidly as it pushed toward land.
Stewart of the University of Plymouth said the study is interesting, but remains cautious about blaming the newfound thrust fault for the A.D. 551 event.
"The Mediterranean has a lot of big earthquakes and there are lots of benches [unstable, newly formed fronts of lava deltas] everywhere. It is hard to link those benches to a particular fault," he said. (Related: "Ancient Tsunami Smashed Europe, Middle East, Study Says" [December 4, 2006].)
Nonetheless, he believes that the risk of another big earthquake occurring is very high, and should be taken seriously.
"In the past this area has had a lot of big earthquakes and tsunamis, but in modern history it has been quite quiet," Stewart said.
"We have been lulled into a false sense of security, just like we were in the [2004 Indian Ocean earthquake]."
Drowned Cities
Archaeological and historical evidence of the A.D. 551 earthquake indicate that this was truly a catastrophic event.
All the major coastal cities between Tripoli and Tyr suffered heavy damage, with Tripoli reported to have "drowned."
Historical records describe "the complete ruin of Berytus (Beirut), Jewel of Phoenicia, and the sea retreating one to two Roman miles, or 4,921 to 9,842 feet (1500 to 3000 meters) from shore. That's enough to ground mooring ships and uncover sunken ones. More than 30,000 people died in Beirut alone. (Who were the Phoenicians?)
"If this earthquake and tsunami were repeated today, it would be a disaster of enormous proportions," said Sanford Holst, an author and expert on ancient Phoenicia.
More than 70 percent of the Lebanese population lives along the coast: Beirut has a population of 1.5 million.
What's more, much of the country's infrastructure is also located along the coast. The main highways, electrical power stations, airports and economic centers are all next to the sea, Elias said.
To prepare for the next big quake, many of the tall buildings that line the coast need to be re-enforced to withstand earthquakes. New buildings need to be built with large earthquakes in mind. And people need to be informed. "We need an earthquake and tsunami alert system and proper emergency plans," Elias said.
Earthquake?! On Earth? Ah, go on....
Such a quake off Lebanon would also do serious damage in Israel, and there is similar massive quake potential within Israel itself.
Don't bother trying to reason with such people - I've seen people gloating over quakes occuring in Christian areas of Indonesia because they thought they were Muslim areas.
Just wondering.
A tiny fraction of what used to live there.
Incidentally, you forgot the "children". Want to give it another go?
Indonesia: muslim - 88%; Christian, 8%.
OK quick where are the "Christian" areas?
Any rational human being assuming the victims are muslim, have an 11 to 1 chance of being right.
Just saying.
A recent Discovery Channel special was about the “zipper” effect in turkey. Earthquakes have been moving along that zipper from east to west with great regularity, the next ZIP is just off shore from istanbul, and given the pattern, that’s REAL soon.
Yes, I saw that one, you're correct. It's been a while since I saw it though.
My oldest son lives in Brooklyn but went to istanbul last christmas on vacation. Interesting city, 7 layers of different architectural styles/cultures can be seen. Very friendly people. He went to an armenian church service, like jumping back a 1000 years in time with ancient costumes/rites. Then the Hagga Sofia, crusader castles; sad to think that if this next ZIP is as strong as they predict, all of Istanbul will basically be leveled. Sad too because Turkey is a stable country and a member of NATO because of the russian BEAR to the north, they have a problem w/the kurds but al queda knows to stay away from it.
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Thought you may be interested in seeing this, Quix...
The Book of Revelation predicts that shortly before the Lord comes back, a major earthquake in Jerusalem will kill 7,000. Perhaps this is what causes it.
Sounds like L.A.
Where does it say that???
"Eastern United States overdue for large earthquake."
"Illegal alines overdue to suck up funds bankrupting Social Securty and Medicare/cade."
"There's a sale at Penney's!"
Nah, I thought the same thing.
11:13
L.A. has those every once in a while — “Waterworld” for example.
The New Madrid fault, where Missouri, Tennessee and Arkansas come together has been predicted to rip by many experts over the years. There have been a few small vibes...
Same thought occured to me.
The fact remains this, like the predicted New Madrid earthquake that wasn’t, is just a guess.
And we don’t yet know enough to dare call it an ‘educated guess’.
I’m not going to gloat, as I’ve lived on one fault line or another for the last 40 years. Several US areas are due for the “big one” any minute too.
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