Earthquakes can trigger others half way around the world
May 25, 2008
AP
A major quake such as the one that left at least 60,000 dead in southwestern China this month can trigger other earthquakes half way around the world, according to a study released Sunday.
This unexpected finding could one day help make better predictions about the frequency and intensity of aftershocks, the lead researcher told AFP.
A team of geologists in the United States found that 12 out of 15 major quakes -- registering a magnitude of 7.0 or higher -- since 1990 generated surface waves that set off smaller seismic events in fault systems on distant continents.
The China quake, which measured 8.0 on the Richter scale, was not included in the study, which was published in the British journal Nature Geoscience.
"It was known that these surface waves could travel," explained co-author Tom Parsons of the US Geological Survey.
"But most scientists thought these so-called dynamically-triggered earthquakes were a special case. In fact they happen all the time, everywhere, and that was something of a surprise," he said in a phone interview.
The terrible December 2004 mega-quake off the coast of Sumatra, Indonesia, for example, provoked seismic events as far away as Alaska, California and Ecuador.
There is a better than 95 percent likelihood that the earthquake rate in distant areas will be much higher in the immediate aftermath of a big quake than before or after, the study found.
And while the seismic movements triggered by far away quakes were generally smaller -- in the three-to-five magnitude range -- there is no reason they could not be as big or bigger than the first.
"They could be any size," said Parsons, who in previous research identified eight cases in the last quarter century in which a 7.0-or-bigger earthquake led to another that was even larger.
To measure the impact elsewhere on the planet of major tremblors, Parsons and colleagues analysed broadband seismographs from over 500 stations, part of a worldwide monitoring network.
By searching for the lowest frequencies and filtering out the highest, they detected a sharp increase in the number of distant quakes triggered by a main quake, even though the tectonic environment of the two regions were independent.
"The big question is aftershocks, and what happens after you have a big earthquake," said Parons, adding that there are two competing theories as to how such follow-on quakes are unleashed.
Static triggering occurs within a few fault lengths of the main rupture, often in a cascading effect. But impact generally peters out beyond a 100-to-200 kilometre (70-to-140 mile) radius.
The spike in quake activity further afield can only be explained by dynamic triggering, explained Parsons.
Such seismic waves travelling along the surface of the earth "keep their amplitude and do not diminish that much even over great distances," he said.
The key to predicting the aftermath of a quake such as the one in China will be teasing apart the role of static and dynamic triggering.
"We can look at the aftershocks and start to learn, but we need to know what percentage of those are dynamically triggered because the effect isn't lasting, it's transient," Parsons explained.
"Once those waves are gone, the effect is mostly over with, we really don't have to worry about that any more."
http://www.breitbart.com/article.php?id=080525173254.8uczuvwc&show_article=1
Study: Large Earthquakes Do Trigger Other Quakes
May 25, 2008
Ed Yeates reporting
KSL TV5
Everybody has theorized about it for years, but now there's proof! Large earthquakes do, in fact, trigger other earthquakes, sometimes on the opposite sides of the Earth.
In 1992, a magnitude 7.3 earthquake hit Landers, Calif. Within minutes and hours of that Lander's event, a quake rattled Las Vegas. Then 60 small quakes broke loose near Cedar City. Quakes also hit two volcanic locations on California's Cascade Range. And quakes showed up in old craters in Washington state and Yellowstone Park.
Scientists had believed large quakes cannot trigger other quakes hundreds of miles away, but apparently, they can. In fact, University of Utah seismologist Chris Pankow and her colleagues, who've carefully analyzed two different kinds of surface shock waves from 15 major earthquakes over the past 16 years, say the triggering occurs not only hundreds, but thousands of miles away.
Chris Pankow, a University of Utah seismologist, says, "What we clearly found from the Sumatra earthquake is a triggered event in Ecuador, which is at the antipode - so opposite side of the globe - there was triggering."
The triggered earthquakes are smaller, but they happen globally and sometimes in areas not prone to earthquakes. So, why are some faults triggered by a distant event? One theory, Pankow says, is "You have something really ready to go, and you just put a little energy, and that sort of accelerates the time on the fault to failure."
Another theory says shock waves shake the pores loose in geothermal areas like Yellowstone Park or places with a high water table. In some cases, increased fluid pressure may actually lubricate a fault, so it slips a bit.
Seismologists don't know for sure what's happening on the receiving end, but now that they do know triggering occurs, they'll move to the next step, hoping to understand the mechanics. "It's happening everywhere following large earthquakes, and that is exciting and really interesting to me as a scientist," Pankow said.
Another possibility: could a different kind of earth mechanics, involving what seismologists call static stress, affect our own Wasatch fault? One 25 mile section of the fault breaks loose with a magnitude 7 or greater earthquake, triggering yet another quake on another section of the fault. It could happen!
The University of Utah partnered with the University of Texas and the United States Geological Survey for this landmark research. The full study appears today in Nature Geoscience.
http://www.foxnews.com/story/0,2933,354692,00.html
Moderate quake hits Panama-Costa Rica border
PANAMA CITY (Reuters) - A moderate earthquake of 5.2 magnitude struck on the Pacific coast side of the Panama-Costa Rican border on Monday, the U.S. Geological Survey said, but only minor structural damage was reported.
The quake, which hit at 10:01 a.m. local time (4:01 p.m. British time), was centred 135 miles (217 km) southeast of San Jose, Costa Rica, and at a depth of about 22 miles (35 km), the USGS said.
The only initial report of damage was of cracks in the walls of a school in the Baru region of Panama, near the country's only active volcano, a spokeswoman for Panama's civil protection service said.
(Reporting by Andrew Beatty; Editing by Eric Beech)
© Thomson Reuters 2008 All rights reserved.
CHENGDU, China: The teahouses are nearly empty, travel agents sit beside silent telephones and shopkeepers pass the day watching the ongoing agony of their countrymen on television. The buildings in this usually teeming city of 10 million, about 80 kilometers east of the epicenter of the May 12 earthquake, may be unscathed, but its residents are living on edge.
"Everyone is paralyzed with dread, and each new tremor just prolongs our misery," said Wu Longyou, a crafts vendor presiding over a nearly deserted outdoor shopping mall that normally pulses with foreign tourists. "We are still alive, but we are suffering too."
The powerful aftershock that struck northern Sichuan Province on Sunday sent thousands of residents here running into the street. There was little damage in Chengdu, but the aftershock, with an estimated magnitude of 6.0, killed at least 8 people, injured more than 400 and toppled 70,000 buildings in the mountains to the north, according to the government.
It also renewed the terror for millions of earthquake survivors who are living in tent camps, subsisting on instant noodles and waiting for the earth to stop shaking. On Monday, government officials issued fresh warnings that 69 fragile dams and several rivers blocked by mammoth landslides were looming threats to tens of thousands of people living downstream. On Tuesday, they raised the death toll from the May 12 earthquake to more than 67,000.
Here in Chengdu, the provincial capital of Sichuan, each new tremor rattles the collective psyche of a city that escaped serious physical damage but has lost its joie de vivre. Local officials estimate that as much as a third of the population has left town; many of those who remain spend their nights in tarp-and-tent shantytowns.
Those with the means drive out to the countryside and bed down in their cars. "I don't want to die in my sleep," said Dan Chao, 13, explaining why he and his parents refuse to spend the night in their third-floor apartment.
Chengdu is in a stranglehold of fear. On May 19, a week after the earthquake struck, a local television station broadcast a warning just before midnight that a 6.7 magnitude aftershock was on the way.
Streets quickly clotted with fleeing vehicles and parks filled with families and their bedding. The big aftershock, however, never came.
For the last two weeks, students at Sichuan University have slept in their track suits; many keep their dormitory room doors open to allow for a quick escape. "We joke that it would be embarrassing to have to run outside in our underwear, but actually I think we are all afraid," said Deng Minkuei, 19, a sophomore, who, like most of his classmates, keeps a knapsack with water and biscuits by the door. "To spend two weeks waiting for another earthquake is not good for your health."
While government officials say the earthquake's impact on the national economy will be small, the toll on Chengdu is expected to be enormous. The city is a tourist gateway to ancient monasteries and a world-famous panda reserve, which sit at the heart of the disaster zone. Tour operators say business, even in parts of the province untouched by the earthquake, has disappeared.
"After they see the news, no one wants to come here," said Yu Jia, a Chengdu travel agent sitting glumly at his desk. "Everything is dead. Maybe it will be like this for a year."
Many of the city's hotels are nearly empty, although a few of the newest ones - those that claim to be "quake resistant" - have seen an influx of journalists and foreign relief workers.
Wu Longyou, 40, an artisan who weaves palm fronds into the shapes of insects and animals, said he had barely made any money since the quake struck. This week he is heading to Hangzhou, a city more than 1,400 kilometers, or 900 miles, to the east, where there are plenty of tourists. "If I stay here any longer I'm going to starve," he said.
Not everyone is complaining. Xu Jianquan, who runs a local real estate company, said business had been brisk, although most people were seeking apartments in new buildings.
As he spoke, two men sat in his office making a deal for a rental unit in a building constructed in 1990. The prospective tenant, Zhen Deyun, said he would have preferred a ground-floor apartment in a modern building but decided the third floor would have to do.
"From what I can tell, it's relatively good construction," said Zhen, 38, a stock analyst, who, along with his mother, is moving from an older building on the city's outskirts. "Of course, if an 8.0 magnitude earthquake hits Chengdu, nothing will be safe."
Such insecurities play out in unpredictable ways. High-end hair salons and massage parlors say they have seen a slight rise in customers seeking to be pampered, while stores that sell alcohol say business is off by a third. "Maybe people don't feel like celebrating, or maybe they don't want to be drunk when an earthquake comes," said one liquor store clerk, standing in an empty shop.
Wu Min, 43, a lottery ticket vendor, had her own theory for why sales were down by half. "When people are anxious or in a bad mood, they will not pick good numbers," she said. "They are just waiting for the aftershocks to stop."
So, too, are the hundreds of people who have turned the leafy promenade along the Funan River into a cavalcade of red, white and blue tarps. Tan Yuquan and his neighbors have stocked their encampment with beds, plastic chairs, playing cards and mosquito coils. The mood was buoyant Monday night, with neighbors chatting late into the night as children ran up and down the sidewalk. "It makes us all closer," Tan, 60, a candy salesman, said as he passed out cigarettes to the crowd.
His wife, Hou Xiaorong, 42, was less sanguine. After two weeks, she said she was growing weary of the lack of privacy and the noise from cars passing a few meters from their pillows.
"I guess it can always be worse," she said. "Living on the street isn't so great, but it's better than waking up with a building falling on your head."
Visions of New Madrid Quake
Pastor John Kilpatrick
watch@churchofhispresence.org
Daphne, Alabama
Sunday, April 27, 2008 - Vision
As I was approaching the Daphne Civic Center for Sunday morning service at Church, I had a vision which lasted for about two or three seconds. In this vision, I saw the ground buckling before me. It was so real that I actually moved aside to avoid what I was seeing. I knew immediately that it was an earthquake, and the thought crossed my mind that the damages of this earthquake could have the potential to exceed those of Hurricane Katrina of 2005.
WIND and WATER
May 20, 2008
I awoke trembling at 5:00 in the morning after having a startling dream. This was one of the three most profound dreams that I have ever had during the ministry the LORD has called me to. I feel that this dream is an addendum to the vision I had on April 27, 2008.
I saw the words wind and water. I only saw the words but did not actually see any wind or water damage. I then found myself overlooking a river which instantly became so wide that I could no longer see either of its banks. The dream then shifted, and I was with one of my parishioners running through what appeared to be an old abandoned school house. This empty building began to shake. The shaking was so violent and severe that it was like the bucking of a wild horse tossing us around. My teeth were clapping so hard from the impact that I tried to clinch them to prevent this from happening.
In this dream I knew I was experiencing a massive earthquake. The sounds were so catastrophic that the thought crossed my mind that the devastation could likely exceed Hurricane Katrina of 2005. I did not see the devastation behind me, I only heard it. In all of my life I have never heard such catastrophic sounds. These were the scariest sounds I have ever heard. The dream then shifted once more and concluded with two names on what appeared to be an old Spanish map. One name read Indianola and the other Europa.
I researched the internet and contacted some close friends in the ministry and reliable intercessors concerning this dream. What we found was startling. There are towns called Indianola, IL, Europa, MO, and Indianola, MS. These towns run in a line from North to South with Europa, MO being near the middle of them. The Mississippi River runs between them with Europa, MO being by the epicenter of the New Madrid fault. After seeing this, I believe the dream could be concerning a devastating earthquake on the New Madrid fault.
God gave me this as warning to prepare us for the days ahead and to pray concerning this matter. I did not see any time frame as to when this may happen.
'Barrier Lake' in China Threatens Up to 1.2 Million in Earthquake Zone
May 27, 2008
By Don Lee
Los Angeles Times
MIANYANG, CHINA -- The government warns that evacuations may be necessary because of the risk of flooding from a swelling lake formed north of Beichuan. Debris and landslides formed about 35 such lakes after the quake.
The Chinese government warned today that as many 1.2 million residents may have to be evacuated because they could be inundated by a swelling "barrier lake" formed by the May 12 earthquake.
Photo: In Sichuan Province, quake lakes like these formed as water levels ascended and dams were destabilized by the upheaval of May 12. (Xinhua News Agency)
The notice was issued hours after a Russian helicopter transported heavy machines over mountains in the northern part of Sichuan province, and hundreds of Chinese soldiers carried in 10 tons of dynamite, to contend with the barrier lake at Tangjiashan, about 2 miles upstream from the town of Beichuan.
The afternoon announcement, broadcast on local television, made for another jittery day in Mianyang, a municipality of 5 million people that includes some of the hardest-hit areas of the earthquake, including Beichuan. Hopes of normality returning to the region had already been set back by Sunday's magnitude 6 aftershock, centered north of here, which killed eight people and destroyed or damaged 270,000 houses.
Monday's flood warning prompted some people to haul their tents to higher ground and others to flee Mianyang altogether.
"Some of my friends are leaving town; they want to go as far away as possible," said Liu Decai, 35, a taxi driver who drove home after the broadcast to pack up jewelry and other valuables.
China's central government continued to stress the importance of resettling victims, restoring production and rebuilding devastated areas. Some 5 million people were left homeless by the quake, which has claimed more than 65,000 lives, with 23,150 people still missing.
In addition, more than 306,000 were injured by the quake. As of Sunday, 5,914 patients were moved from overloaded hospitals in Sichuan province to medical centers elsewhere in the country, with another 2,100 still to be transferred, said the Ministry of Health.
Even as officials shift the focus from rescue to caring for survivors and preventing epidemics, they are trying to avert a potential disaster from some of the 35 barrier lakes that formed when rivers were plugged by landslides triggered by the quake. Geologists worry that aftershocks or heavy rains could burst the barriers.
One of the largest and most threatening is the one at Tangjiashan, which now holds more than 4.5 billion cubic feet of water and, as of today, was only 85 feet below the lowest part of the barrier, according to the official New China News Agency.
Tonight, about 600 engineers and soldiers had gathered at the blockage of the lake and were planning to work through the night to remove debris from a sluice, the agency said. Soldiers also might set off small-scale blasts to help drain the water.
Tens of thousands of people already have been evacuated. The warning issued today said that in the worst-case scenario, in which the entire barrier collapsed, about 1.2 million people would be ordered to move to higher ground, including some in central Mianyang.
"Right now, there is not panic in the tent city," said Mianyang spokesman Wang Xiaogang, referring to the thousands of people living in tents at Jiuzhou Stadium.
But many others in downtown Mianyang weren't taking any chances.
The Fucheng District Christian Church in Mianyang, with more than 4,000 members, called off all activities, including serving lunch to those at the stadium, to prepare for the evacuation, said the Rev. Ma Jin.
"We are now transferring some important documents to high ground, so if a flood comes, they won't be destroyed," the pastor said. "And of course I will pray too."
Cao Jun of the Times' Shanghai bureau contributed to this report.
http://www.latimes.com/news/nationworld/world/la-fg-china27-2008may27,0,1933996.story
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