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Topic: Geology (Read 2468 times)
February 02, 2009, 07:24:26 PM »
Chinese earthquake may have been man-made, say scientists
An earthquake that killed at least 80,000 people in Sichuan last year may have been triggered by an enormous dam just miles from the epicentre
By Malcolm Moore in Shanghai
Last Updated: 12:06AM GMT 03 Feb 2009
Destroyed buildings in the earthquake-damaged town of Beichuan, Sichuan Province, China Photo: AFP/GETTY
The 511ft-high Zipingpu dam holds 315 million tonnes of water and lies just 550 yards from the fault line, and three miles from the epicentre, of the Sichuan earthquake.
Now scientists in China and the United States believe the weight of water, and the effect of it penetrating into the rock, could have affected the pressure on the fault line underneath, possibly unleashing a chain of ruptures that led to the quake.
Fan Xiao, the chief engineer of the Sichuan Geology and Mineral Bureau in Chengdu, said it was "very likely" that the construction and filling of the reservoir in 2004 had led to the disaster.
"There have been many cases in which a water reservoir has triggered an earthquake," said Mr Fan. "This earthquake was very unusual for this area.
There have been no seismic activities greater than a magnitude seven quake along this particular seismic belt before."
The 7.9 magnitude quake struck last May and left more than five million people homeless. It remains a raw and emotional topic for most Chinese, and the government has been quick to quash any suggestion that Zipingpu may have been responsible for the catastrophe. Researchers have been denied access to seismological and geological data to examine the earthquake further.
Zipingpu is only one of nearly 400 hydroelectric dams in the earthquake zone. Mr Fan said the government had been warned of the danger of building so many large-scale projects in a seismically active area, but that the warnings had gone unheeded.
"I not only opposed the construction of Zipingpu, but also the overdevelopment of the reservoirs on Minjiang River. There are ten major reservoirs on the main river, 29 on its tributaries and a lot more smaller-scale reservoirs, all of which block the flow of the entire river, and are very hazardous to the local geology," he said.
Although Sichuan is an earthquake-prone region, many scientists were caught by surprise by the magnitude of the quake. Christian Klose, a scientist at Columbia University's Lamont-Doherty Earth Observatory, said there had not been any "major seismic activity" on that fault line for millions of years.
He argued that the sudden shift of a huge quantity of water into the region could have simultaneously relaxed the tension between the two sides of the fault, allowing them to move apart, and also increased the direct pressure enough to cause a violent rupture. The effect was "25 times more" than a year's worth of natural stress from tectonic movement, he said.
Although the official government line is that its massive construction projects had nothing to do with the quake, some state researchers in Beijing have called for a full investigation. Lei Xinglin, of the China Earthquake Administration, said that the Zipingpu reservoir "clearly affected the local seismicity and it is worthwhile to study the role it played in triggering the earthquake further". He added that firm conclusions remain "premature" however.
There is a history of earthquakes triggered by dams, including several caused by the construction of the Hoover dam in the US, but none of such a magnitude.
Reply #1 on:
April 06, 2009, 12:32:38 PM »
I wonder what should have been done. You ask everyone to evacuate? Give how to survive an earthquake lessons?
Warn everyone and those who want to leave the area can?
Have emergencies on alert? What actually would we do?
Suppose a scientist starts warning LA there is an imminent Eq. What should be done?
Now that we have made natural disasters the fault of someone such as Katrina, et al.
Naturally, we can now say this was someone'e fault. Hey you were warned and the dirty gov covered it up.
***Italy muzzled scientist who predicted quake
ROME (Reuters) – An Italian scientist predicted a major earthquake around L'Aquila weeks before disaster struck the city on Monday, killing more than 100 people, but was reported to authorities for spreading panic.
The government on Monday insisted the warning, by seismologist Gioacchino Giuliani, had no scientific foundation but Giuliani said he had been vindicated and wanted an apology.
The first tremors in the region were felt in mid-January and continued at regular intervals, creating mounting alarm in the medieval city, about 100 km (60 miles) east of Rome.
Vans with loudspeakers drove around the town a month ago telling locals to evacuate their houses after Giuliani, from the National Institute of Astrophysics, predicted a large quake was on the way, prompting the mayor's anger.
Giuliani, who based his forecast on concentrations of radon gas around seismically active areas, was reported to police for "spreading alarm" and was forced to remove his findings from the Internet.
"Now there are people who have to apologize to me and who will have what has happened on their conscience," Giuliani told the website of the daily La Repubblica.
Giuliani, who lives in L'Aquila and developed his findings while working at the National Institute of Nuclear Physics in the surrounding Abruzzo region, said he was helpless to act on Sunday as it became clear to him the quake was imminent.
"I didn't know who to turn to, I had been put under investigation for saying there was going to be an earthquake."
AGENCY REASSURED TOWNSPEOPLE
As the media asked whether, in light of his warnings, the government had protected the population properly, Prime Minister Silvio Berlusconi seemed on the defensive at a news conference.
He said people should concentrate on relief efforts for now and "we can discuss afterwards about the predictability of earthquakes."
Italy's Civil Protection agency held a meeting of the Major Risks Committee, grouping scientists charged with assessing such risks, in L'Aquila on March 31 to reassure the townspeople.
"The tremors being felt by the population are part of a typical sequence ... (which is) absolutely normal in a seismic area like the one around L'Aquila," the agency said in a statement on the eve of that meeting.
It said it saw no reason for alarm but was nonetheless carrying out "continuous monitoring and attention."
The head of the agency, Guido Bertolaso, referred back to that meeting at Monday's joint news conference with Berlusconi.
"There is no possibility of predicting an earthquake, that is the view of the international scientific community," he said.
Enzo Boschi, the head of the National Geophysics Institute, said the real problem for Italy was a long-standing failure to take proper precautions despite a history of tragic quakes.
"We have earthquakes but then we forget and do nothing. It's not in our culture to take precautions or build in an appropriate way in areas where there could be strong earthquakes," he said.***
Krakatoa's New Eruptions
Reply #2 on:
July 31, 2009, 12:33:24 PM »
Very image heavy piece about Krakatoa's new eruptions. The pics are all impressive, like this one:
Reply #3 on:
November 11, 2010, 05:45:13 PM »
Some astounding pictures of Mount Merapi's eruptions:
Including this one:
Reply #4 on:
May 09, 2011, 10:16:34 PM »
Holding on in Rome.
Last Edit: May 09, 2011, 10:19:21 PM by prentice crawford
Iceland's Eruption . . . From Space
Reply #5 on:
May 23, 2011, 02:40:15 PM »
Weather satellites capture shots of volcanic plume blasting through clouds
[Note: at the bottom of this post is a gallery of volcano pictures taken from space.]
Just in case you forgot that the Earth is one of the most geologically active worlds in the solar system*, the Icelandic volcano Grimsvötn has sent a very loud reminder: after seven years of relative inactivity, the volcano woke up on Saturday, rocketing a plume 11 kilometers (7 miles) into the air. The ash column blasted through the cloud layer, and was seen by weather satellites in space! Check out this amazing animation:
That was the view from the Meteosat-9, a European satellite in geostationary orbit. The animation is composed of visible light images and covers just under a three hour time span on May 21. You can clearly see the plume breaching the cloud layer and spreading out, then a second plume blowing through shortly thereafter. The shadow of the plume on the clouds gives an excellent but eerie sense of the scale of this event.
Here’s a similar view from the US GOES 13 satellite showing 3.5 hours of the eruption:
Note the oblique angle and distance; GOES 13 orbits the Earth far west of the volcano. In the last frame of the animation you can see the outline of Iceland to give you an idea of the size of this event.
This volcano has erupted many times over the past few decades. I knew Iceland was active, but what really brought it home to me in this case was a quote by a company that operates the airport facilities in Iceland, when a 220 km no-fly zone around the volcano was established: it was described as "standard procedure around eruptions".
Yikes. The fact that they even need a "standard procedure" is eyebrow-raising to me; where I live, volcanoes are somewhat rare (maybe more so now than a millennia ago). However, this eruption doesn’t currently look like it will be a big danger to air travel like last year’s eruption of Eyjafjalajökull was; the ash is made of bigger particles which fall to the ground more quickly, and the volcano itself is located in a relatively isolated part of southeast Iceland.
Still, clearly, researching volcanoes and their eruptions is critical to many areas of life. Besides the knowledge added to our basic scientific understanding of geology and the Earth, monitoring and understanding volcanoes has a huge impact on air traffic, weather, and the daily lives of millions of people.
Image credits: EUMETSAT; NOAA. Tip o’ the caldera to Jonatan Gislason.
I love these satellite views of volcanoes from space, and I’ve collected quite a few into a gallery slideshow. Click the thumbnail picture to get a bigger picture and more information, and scroll through the gallery using the left and right arrows.]
There are a handful of volcanoes in the world that evoke an immediate recognition, dormant or not. Vesuvius, Krakatoa, Mt. St. Helens. Certainly, Sicily's Mt. Etna is another. At 3300 meters in elevation, it's the largest active volcano in Italy... and by active, I do mean active.
In 2002, Etna erupted in a relatively large display of lava and ash. This view was taken by Expedition 5 about the International Space Station, looking southeast at a low angle. This eruption let loose a river of lava down the flank of the volcano which set fire to pine trees there; the dark plume is from the eruption, but the whiter ones are from burning pine trees. The plume from this eruption blew south and was reported as far away as Libya, nearly 600 km distant.
Unlike Earth observing satellites, which point straight down, astronauts on the ISS have the luxury of seeing things at an angle, providing a more natural - and in this case, more spectacular - view to our human eyes and brain.
Re: Iceland's Eruption . . . From Space
Reply #6 on:
May 23, 2011, 04:18:06 PM »
That is amazing. A good reminder how small we are.
Reply #7 on:
August 23, 2011, 01:58:58 PM »
(AP) — A 5.9 magnitude earthquake centered northwest of Richmond, Va., shook much of Washington, D.C., and was felt as far north as Rhode Island, New York City and Martha's Vineyard, Mass., where President Barack Obama is vacationing.
The U.S. Geological Survey said the earthquake was half a mile deep. Shaking was felt at the White House and all over the East Coast, as far south as Chapel Hill, N.C. Parts of the Pentagon, White House and Capitol were evacuated. There were no immediate reports of injuries.
It was centered near Louisa, Va., which is northwest of Richmond and south of Washington.
Obama and many of the nation's leaders were out of town on August vacation when the quake struck at 1:51 p.m. EDT. The shaking was felt on the Martha's Vineyard golf course as Obama was just starting a round.
The East Coast gets earthquakes, but usually smaller ones and is less prepared than California or Alaska for shaking.
At Reagan National Airport outside Washington, ceiling tiles fell during a few seconds of shaking. Authorities announced it was an earthquake and all flights were put on hold.
At the Pentagon in northern Virginia, a low rumbling built and built to the point that the building was shaking. People ran into the corridors of the government's biggest building and as the shaking continued there were shouts of "Evacuate! Evacuate!"
In New York, the 26-story federal courthouse in lower Manhattan began swaying and hundreds of people were seen leaving the building. Court officers weren't letting people back in.
The quake came a day after an earthquake in Colorado toppled groceries off shelves and caused minor damage to homes in the southern part of the state and in northern New Mexico. No injuries were reported as aftershocks continued Tuesday.
In Charleston, W.Va., hundreds of workers left the state Capitol building and employees at other downtown office buildings were asked to leave temporarily.
"The whole building shook," said Jennifer Bundy, a spokeswoman for the state Supreme Court. "You could feel two different shakes. Everybody just kind of came out on their own."
In Ohio, where office buildings swayed in Columbus and Cincinnati and the press box at the Cleveland Indians' Progressive Field shook. At least one building near the Statehouse was evacuated in downtown Columbus.
In downtown Baltimore, the quake sent office workers into the streets, where lamp posts swayed slightly as they called family and friends to check in.
Social media site Twitter lit up with reports of the earthquake from people using the site up and down the U.S. eastern seaboard.
"People pouring out of buildings and onto the sidewalks and Into Farragut Park in downtown DC...," tweeted Republican strategist Kevin Madden.
"did you feel earthquake in ny? It started in richmond va!" tweeted Arianna Huffington, president and editor-in-chief of the Huffington Post Media Group.
Missouri Sen. Claire McCaskill tweeted that her staff in Washington was in an "emergency location. Hope everyone is ok."
John Gurlach, air traffic controller at the Morgantown Municipal Airport was in a 40-foot-tall tower when the earth trembled.
"There were two of us looking at each other saying, 'What's that?'" he said, even as a commuter plane was landing. "It was noticeably shaking. It felt like a B-52 unloading."
Immediately, the phone rang from the nearest airport in Clarksburg, and a computer began spitting out green strips of paper — alerts from other airports in New York and Washington issuing ground stops "due to earthquake."
Last Edit: August 23, 2011, 02:09:45 PM by prentice crawford
Michael Yon comments from Afpakia
Reply #8 on:
August 23, 2011, 03:25:41 PM »
Got an email from a friend that the Pentagon evacuated, and I see reports saying the same. Get back to work you Pentagon shammers! If the military panics, everybody panics. The Pentagon took a direct hit from an airliner and is still there. The Japanese will be laughing at the Pentagon. Get back to work you bunch of Pentagon ninnies. We have wars to run!
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