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ElishevaBarsabe Really?!
Great Old One Joined: 19 Mar 2002 Total posts: 942 Location: in the fog Gender: Female |
 Posted: 29-09-2004 05:41 Post subject: |
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| Fallen Angel wrote: |
We felt that one here in the Bay Area. About 20 seconds or so of mild rolling movement.
Hardly enough to take notice of.  |
I'm so glad that you wrote here. My husband and I felt this one, too, in Santa Cruz, and guessed that it lasted around 20 seconds, which is a fairly long time for such things. Didn't feel any of the aftershocks, however. |
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| marslight avatarically challenged Joined: 23 Aug 2004 Total posts: 416 Location: The Big Orange Gender: Male |
| Posted: 29-09-2004 06:27 Post subject: quake du jour |
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Did anyone here in the L. A. area feel it? I didn't, but I was on the freeway at the time.
Question: Which is more scary; the hurricane you have plenty of warning for, or the earthquake that rudely barrels through and is gone in less than a minute? |
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| ramonmercado Psycho Punk
Joined: 19 Aug 2003 Total posts: 17933 Location: Dublin Gender: Male |
| Posted: 29-09-2004 13:41 Post subject: Predicted earthquake arrives - 16 years late |
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Predicted earthquake arrives - 16 years late
13:04 29 September 04
NewScientist.com news service
The magnitude 6 earthquake that rocked central California on Tuesday may have been the most widely anticipated earthquake in history. It will almost certainly also turn out to be the most precisely measured earthquake ever.
The location and magnitude of the earthquake had been predicted. But the problem for forecasters was that it happened about 16 years later than expected.
The tiny town of Parkfield, with a population of 37, is the only location for which the US Geological Survey has ever issued a detailed earthquake prediction. Magnitude-6 earthquakes had been recorded there about every 22 years between 1857 to 1966, leading the agency to issued a formal prediction that another magnitude-6 quake would strike the area sometime around 1988.
As a result, the USGS and various universities have blanketed the small town with an array of the most sophisticated monitoring devices ever installed in a single area, USGS scientists say.
Lasers and mirrors
The instrumentation includes lasers and fixed mirrors on opposite sides of California's famed San Andreas Fault, which runs through the town. These measure the exact movements of the land before, during and after the shock.
Other instruments monitor water levels and trace gases in deep wells, and the strain levels in the bedrock. Many of the devices are tended by the sole teacher in the town's one-room schoolhouse, and monitored remotely by scientists in various locations.
Because the epicenter was in such a sparsely populated rural area, initial reports indicated that there were no injuries and very little damage to buildings or other structures. But the quake was felt by people across a 400-mile-wide region of California, from San Francisco down to south of Los Angeles.
Data bonanza
The initial quake struck at 1015 PDT (1815 BST), with an epicenter estimated to be about 11.2 kilometres (7 miles) southeast of Parkfield and 7.8 km (4.9 miles) below ground. Since then about 200 smaller aftershocks have been recorded.
The USGS estimates there is a 5% to 10% chance that an earthquake even larger than the first could rock the same area in the next few days.
A magnitude 6 earthquake out in the countryside is far from being the "Big One" of magnitude 7 or more that has been widely anticipated to strike the Los Angeles area. But for seismologists, this is a long-awaited bonanza of data.
The measurements will be used to better understand the dynamics of earthquakes in California. It will also be scanned for any changes that happened before the quake, which might one day be used to make reliable predictions.
"The jury is still out about whether the earth gives out reliable signals about whether an earthquake can be predicted," the USGS's Mike Blanpied told Associated Press.
David L Chandler
http://www.newscientist.com/news/news.jsp?id=ns99996460 |
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| Mighty_Emperor Divine Wind
Joined: 18 Aug 2002 Total posts: 19943 Location: Mongo Age: 42 Gender: Male |
| Posted: 30-09-2004 01:47 Post subject: |
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| Quote: | 'Future earthquakes will be predicted by doctors'
TIMES NEWS NETWORK[ WEDNESDAY, SEPTEMBER 29, 2004 06:15:03 PM ]
PUNE: Exactly eleven years ago, on September 30, 1993, after the Ganesh immersion, a devastating earthquake had rocked Killari, Latur, Osmanabad and the Marathwada region killing thousands of people.
The tragic incident followed a series of debate and discussions on the need to pump money for seismic research in India. While some felt that there was an urgent need to deploy geophysical and seismological instruments in quake prone areas some were of the view that earthquake cannot be predicted.
The TOI spoke to renowned research seismologist from Pune Arun Bapat who is busy promoting a new theory -- There exists a human earthquake precursor and the medical practitioners can help seismologist in early prediction of the earthquakes.
Bapat was the head of the Earthquake Engineering Division of the Central Water and Power Research Station (CWPRS), a government of India undertaking.
After his retirement in 1998, he is working as a consulting seismologist and researcher and is currently the member of the statutory boards and disaster management committees appointed by the state governments of Maharashtra, Himachal Pradesh and Gujarat.
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Excerpts from an interview.
How can medical practitioners help predict earthquakes?
About ten to twenty hours before the occurrence of any moderate to large earthquake most of the animals, birds, fishes, insects etc become restless and make noise. This is known to most of the people and it has been found to be quite reliable seismic precursor.
Similar to the animal precursor, there exists a human precursor which could be monitored by medical practitioners.
After the Spitak (Armenia) earthquake in 1989, which claimed 25,000 lives, an extensive post seismic survey and analysis was conducted.
It was found that the number of deliveries and abortions -- reported one or two days before earthquake, were five times more then the normal average.
Similarly, the number of patients suffering from blood pressure, headache, heart trouble, respiratory diseases, restlessness etc had increased disproportionately. All patients of such diseases had complained of acute trouble, restlessness or disorder when there was apparently no provocative reason. The Spitak research reports states that in future earthquakes will be predicted not by PhD scientist but, by medical doctors.
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Have these findings been verified?
I had conducted some sample surveys at Latur immediately after the 1993 earthquake. On an average in one hospital the number of deliveries per day was about three to four. Two days prior to the earthquake the number had increased to six. It had shot up to 12 a day prior to quake and was 18 on the day of the earthquake.
Similarly, when the OPD records were checked it was found that in different diseases (mentioned above) the rise in number of patients had shown similar trends and it was five to seven times more than the daily average number. During the recent few years the human seismic precursory indicators were checked in China and Turkey and these were found to be similar to what was observed in Spitak.
If this has been verified then why was the help of medical practitioners not sought before the Gujarat earthquake?
The theory is based on non-technological seismic parameters which many researchers are not yet willing to accept. I have already submitted my research papers to authorities concerned.
I am getting good response from the researchers in China and Turkey who too are carrying on the research on similar lines.
In India, we need to promote this theory because we cannot afford to install a large number of seismological and geophysical instruments at thousands of locations. And, in absence of any advanced technological applied mechanism we can use medical watch as an additional technique for seismic monitoring.
A large number of researchers strongly believe that earthquakes cannot be predicted.
This ad-hoc assumption puts an end to epistemological research process in earth science. Also, it casts a long shadow on various disasters mitigating agencies and their efforts.
Currently, most of the efforts are oriented to the post-seismic scenario. These are rescue, evacuation, rehabilitation, acquiring jeeps, mobile hospitals, distribution of food, blankets, tents etc. But these efforts benefit the survivors only. They do not save lives.
Hence, I will be happy if I hear from medical doctors in Srinagar, Shimla, Chandigarh, Dehradun, New Delhi, Pithoragarh, Gangtok, Shillong, Itanagar, Tezpur, Dibrugarh, Kohima, Aizawl, and any other seismically-prone city and town such as Bhuj or Jabalpur. |
http://timesofindia.indiatimes.com/articleshow/867961.cms
Last edited by Mighty_Emperor on 30-09-2004 01:58; edited 1 time in total |
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| Anonymous |
| Posted: 30-09-2004 02:30 Post subject: |
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| Ewww, weird, I opened this thread and we had... an earthquake! Just a little one, maybe a 2.5 or 3, but what timing! |
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| Mighty_Emperor Divine Wind
Joined: 18 Aug 2002 Total posts: 19943 Location: Mongo Age: 42 Gender: Male |
| Posted: 06-10-2004 02:14 Post subject: |
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| Quote: | Posted on Tue, Oct. 05, 2004
Quake forecasts a shaky science
But experts say last week's temblor and others in Parkfield may help them further refine the prediction process
Nathan Welton
The Tribune
It's like Old Faithful.
The San Andreas fault in Parkfield, like the legendary geyser, grumbles regularly -- but predicting its geologic burps with clocklike accuracy has always been a shaky science.
Still, the area might yet be a fount of reliable earthquake activity. Because scientists have predicted a relatively powerful magnitude-6.0 rattler in that area for years, last week's tremor seems to support mathematical models used for long-term quake warnings.
Besides showing that a temblor's strength, location and approximate time -- at least within a multiyear window -- can be reasonably foreseen, scientists say last week's quake also gives credence to other formulas that warn of shakers statewide.
One prediction says a 6.7-magnitude earthquake will hit San Francisco within 30 years, for example. The science behind that warning is similar to the science that forecasted last week's event in Parkfield.
Experts hope to further polish their crystal ball with the help of a 10,000-foot-deep hole they're now boring into the ground in Parkfield, into which they'll place an array of sensors to measure the earth's movements.
While long-term quake prediction appears sound, it's the short-term predictions -- such as warnings in the early 1990s that a quake could hit within days -- that need to be re-evaluated.
"There was nothing there (in Parkfield) that met the rules we set up in the '80s," explained Andy Michael, a U.S. Geological Survey seismologist. "We're now looking at the data to see what might have been there that would have been new and interesting or could help us next time" in short-term predictions.
Long-term predictions
In the late 1970s, scientists began tracking seismic activity around Parkfield and developing a statistical warning system for earthquakes.
That system was and still is based largely on the fact that the area has experienced a magnitude-6.0 quake every few decades for the past 150 years.
David Oppenheimer, project chief for USGS Northern California seismic network, said long-term prediction "is not rocket science -- it's just a matter of doing your homework."
The last two Parkfield temblors for which scientists have decent data -- in 1966 and 1934 -- occurred because of the same geologic phenomenon, he said.
North of Parkfield, the San Andreas fault slides along, with one side rubbing in a direction opposite the other. This so-called strike-slip fault -- different from the up-and-down thrust that jolted San Simeon last December -- typically moves smoothly because of relatively frictionless rock beneath the surface.
"There are little pieces inside the fault zone of different kinds of rock that are higher friction," Oppenheimer said. "They get stuck and pop off quakes of lower magnitudes like one and two."
On the south side, however, there lies a bend in the fault line that stalls the continual creeping. Eventually that stall builds up enough force and a stronger quake, such as the one on Sept. 28, occurs.
Oppenheimer said that the geology of the area guarantees the fault will let loose a quake in that area every so often.
Although the numbers say last week's shaker should have happened around 1988, according to Michael, it wasn't statistically late. And while forecasters didn't pinpoint the exact time, they still nailed the location and the magnitude.
In some ways, earthquake prediction is akin to the "best before" date on a milk container: Scientists can predict what's going to happen (a curdle or a quake) and where it's going to happen (in the carton or in Parkfield) but they can't say precisely when.
But they say their mostly accurate predictions validate the methods used to forecast future large earthquakes in metropolitan areas. And in the meantime, scientists are probing the San Andreas fault for clues to improve their accuracy.
"It's still called the Parkfield Prediction Experiment," Oppenheimer said, emphasizing the last word. "We saw some quasi-periodic behavior in the earthquake cycle when we first started in 1979, so the idea was let's get instrumentation in the ground and get funding and record data before a significant earthquake."
In the short term
What could be improved most about earthquake prediction in Parkfield is the short-term warning system, Oppenheimer said, which for years has been in place to caution people of imminent, strong quakes.
For more than two decades, and particularly in the early 1990s, experts continually warned of the possibility of an impending temblor, using a scheme similar to the federal government's current terror alert system.
The warnings have an A through D severity rating and say a quake could theoretically occur within several days.
The system has cried wolf with every alert issued.
The reports are based on two main measurements along the fault in Parkfield: the speed and distance one side moves when compared with the other, and the strength of minor quakes in the area.
Those minor quakes are relatively common -- about 30 shake the state daily.
A key to the prediction system was historical: The last few magnitude-6 Parkfield shakers followed a strong, magnitude-5 foreshock less than 20 minutes before.
So when a magnitude-4.7 tremor occurred in October 1992, scientists for three days warned the public of a 37 percent chance a magnitude-6.0 quake would strike.
It never did.
In 1996, after realizing their cautions came too frequently, scientists redefined the area where a foreshock would have to occur, making it more specific, and increased by 1.5 the magnitude necessary for a foreshock to trigger an alarm.
The future of predictions
Scientists will soon have a new tool to better their understanding of subterranean geology and maybe even improve their ability to accurately predict quakes.
In June, a 182-foot-tall drill began boring a 10,000-foot hole into the Earth on a ranch in Parkfield with the goal of placing hundreds of sensors that will measure temperature, pressure and the tiniest of the Earth's movements.
The goal of the 0 million project, called the San Andreas Fault Observatory at Depth, or SAFOD, is to allow scientists to study how faults work and how earthquakes happen. The fault zone is poorly understood at that depth.
Scientists hope that the information gained during future quakes will help accurately predict earthquakes.
Since drilling began in June on the Bear Valley Ranch, 25 miles northeast of Paso Robles, the rig has already penetrated more than 7,000 feet. Scientists will conclude their drilling in 2007 and then invest 15 years monitoring the fault. |
http://www.sanluisobispo.com/mld/sanluisobispo/news/local/9840045.htm |
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| Mighty_Emperor Divine Wind
Joined: 18 Aug 2002 Total posts: 19943 Location: Mongo Age: 42 Gender: Male |
| Posted: 10-12-2004 20:29 Post subject: |
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| Quote: | Scientists study clues to forecasting California quakes
By Peter Dykstra
CNN
Thursday, December 9, 2004 Posted: 2054 GMT (0454 HKT)
(CNN) -- Two researchers say they've discovered a pattern of tremors deep beneath the San Andreas Fault that someday may yield clues into unlocking the mysteries of California earthquakes.
Robert Nadeau and David Dolenc, from the University of California-Berkeley, used data collected from Parkfield, California, the self-proclaimed "Earthquake Capital of the World." The tiny central California town virtually straddles the San Andreas Fault and has become the epicenter of quake research.
The scientists recorded 110 tremors over a three-year period that preceded two significant quakes -- a 6.5-magnitude quake that killed two people and toppled structures in Paso Robles, California, last December 22, and a magnitude-6 quake centered near Parkfield earlier this year.
The series of tremors, revealed by Parkfield's High Resolution Seismic Network, were centered as deep as 20 miles below the Earth's surface. While the scientists could not say that there was a certain link between the deep tremors and the surface earthquakes, the small, deep rumbles could someday be a tool in forecasting future San Andreas quakes, the researchers say.
David Schwartz, chief of the San Francisco Bay Area Earthquake Hazards Project for the U.S. Geological Survey, said these deep tremors had never been recorded or studied on the San Andreas Fault before the Parkfield project and the Berkeley researchers' work.
Nadeau calls it "a significant advance toward understanding the processes deep in the earth which generate earthquakes."
More significant, perhaps, because a central California segment of the San Andreas may be due -- or overdue -- for a major quake. In 1995, the Working Group on California Earthquake Probabilities estimated a recurrence of a major quake in the Cholame segment of the Fault area to be about 140 years, give or take several decades. The last major quake affecting the Cholame segment was 147 years ago. Cholame is thirty miles east of Paso Robles.
In 1857, the Fort Tejon Quake ripped a 225-mile gash along the San Andreas, including the Cholame region. There were only two deaths in then-sparsely populated California, but today, a similar quake could be a major disaster, with possible impact from San Francisco to the Los Angeles Basin.
The rugged territory near Cholame is still sparsely populated, but seismologists fear that another quake in the Cholame region could trigger a larger disaster. Still, they said such a disaster -- the much-feared "Big One" -- could be decades, or even centuries, away.
At an estimated 7.9 magnitude, the Fort Tejon Quake was more than 10 times as strong as last year's San Simeon Quake. A repeat of the Fort Tejon Quake also would be substantially more severe than either of the biggest California quakes in recent memory.
The 1989 Loma Prieta Quake, which measured magnitude 7.1, killed 62 people and collapsed a section of the Bay Bridge, and the 1994 Northridge Quake, which reached 6.7 magnitude and killed 61 people in the San Fernando Valley.
The Great San Francisco Earthquake of 1906 was estimated between 7.7 and 7.9 magnitude. Some 3,000 people died as a result of the quake, most of them in fires started by ruptured gas lines.
Earlier this year, the magnitude-6 quake centered near Parkfield caused only minor damage, but it thrilled seismologists, one of whom called the temblor "the most well-recorded earthquake in history."
Nadeau emphasized scientists are still a long way from any semblance of accurate earthquake prediction, but "in the future, the hope is that we will be able to give people a notion of when they should be a little more worried, or a little less worried."
Nadeau's and Dolenc's work was published Thursday in the journal Science. |
Source
| Quote: | Tremors rock earth deep beneath San Andreas Fault
Puzzling vibrations baffle researchers
David Perlman, Chronicle Science Editor
Friday, December 10, 2004
Cholame Segment. Chronicle Graphic
Mysterious tremors deep beneath the San Andreas Fault near the quake- prone town of Parkfield are shaking the earth's brittle crust, far below the region where earthquakes normally strike -- and scientists say they can't understand what's happening or what the motions mean.
Seismic researchers are monitoring the strange vibrations closely. But whether the faint underground tremors -- termed "chatter" by some seismologists -- portend an increased likelihood of a major quake in the area is an unsolved puzzle.
Robert Nadeau, a geophysicist at the UC Berkeley Seismological Laboratory, has charted more than 110 of the faint vibrations since they were first detected by the lab's High Resolution Seismic Network in Parkfield three years ago. What concerns Nadeau and his colleagues is that the epicenter of the great 1857 Fort Tejon earthquake, whose magnitude has been estimated at 7.8 to 8, was located almost exactly where the deep tremors are now occurring -- beneath the San Luis Obispo County village of Cholame, some 17 miles south of Parkfield.
The episodes of chatter last from four to 20 minutes and are being recorded from as deep as 40 miles beneath the surface -- up to four times the depth of normal earthquakes, which originate in what scientists call the "seismogenic zone." That zone reaches no deeper than 9 or 10 miles below the Earth's surface.
What's most striking is that deep tremors like the Cholame series have never been recorded before on a strike-slip fault such as the San Andreas, Nadeau said.
"We see this kind of tremor activity inside volcanoes like Mount St. Helens," Nadeau said, "but that's due to the movement of rising magma, and in the tremors we've recorded there's no evidence of volcanism and no seismic waves typical of ordinary earthquakes."
Nadeau and David Dolenc, a graduate student in his lab, are publishing the first report on the mysterious sequence of deep tremors today in Science Express, the online edition of the journal Science. They conclude that "future increases in San Andreas Fault tremor activity may signal periods of increased probability for the next large earthquake on the Cholame segment."
The Fort Tejon event rocked the ground violently and ruptured the fault for 225 miles, from northwest of Parkfield to San Bernardino. It was at least as large as the 1906 San Francisco quake. But because the Cholame region was virtually unpopulated at the time, it killed only two people and destroyed only the Tejon Army post, midway along the affected section of the fault.
The area is still sparsely populated; Cholame itself boasts only 2,125 inhabitants. But Paso Robles, with a population of more than 25,000, is only 25 miles west of the village -- and it was badly damaged by a magnitude 6.5 quake only a year ago.
Scientists have estimated that the Cholame segment of the fault has ruptured in a large quake roughly every 140 years. It is now 148 years since the Fort Tejon event, so the possibility of another one may be steadily increasing, they say.
Similar deep tremors have been detected recently along the coast of the Pacific Northwest, known as the Cascadia Subduction Zone, as well as in Japan -- and there, too, scientists are struggling to understand what their import is. In those areas, giant slabs of the earth's crust are dipping downward and sliding ponderously beneath other great crustal slabs, and scientists believe that fluids -- most likely seabed water saturating the slabs -- are causing the tremors, according to Herbert Dragert of Canada's Geological Survey in British Columbia and Kazushige Obara of Japan's National Research Institute for Earth Science and Disaster Prevention.
In an interview, Dragert said the tremors appear to add stress to a major thrust fault in the Puget Sound region, and that scientists in Canada and Washington are trying to determine whether the tremors might "play a significant role in triggering great earthquakes."
In California, the most mystifying feature of the unexplained tremors is that they are occurring right on the deepest part of the San Andreas -- a fault that does not involve subduction or volcanic activity. Instead, two sides of the earth's crust are sliding horizontally past each other in a motion seismologists call "right-lateral strike slip." In an earthquake, that slip can be an abrupt jolt, and in big quakes, a violent one.
The tremors are occurring at such great depth, Nadeau said, that they must be at the very bottom of the brittle crust -- where the earth's hot, viscous upper mantle begins -- which has been under stress for millions of years.
It's possible that the mantle there resembles something like Silly Putty, Nadeau said, with great chunks of embedded rock grinding against each other to generate the tremor signals. That's purely a speculation, Nadeau conceded, but so far it's the only one around.
"No one really knows what the tremors mean," said David Schwartz, a geophysicist at the U.S. Geological Survey in Menlo Park. "As to what they imply for the possibility of some future quake, we can't tell, and right now we can only wait and see."
A long-awaited magnitude 6 quake struck Parkfield in September at a depth of about 5 miles. That quake was seen as the latest in a series of quakes that have hit around Parkfield on an average of every 22 years between 1857 and 1966.
The Parkfield section of the San Andreas, in southern Monterey County, is the most intensively instrumented seismic danger region in the United States. A borehole 2 miles deep, carrying an array of instruments and called the San Andreas Fault Observatory at Depth, is to be completed next summer.
Whether its instruments solve the mystery of the tremors and determine whether they portend a future Cholame earthquake remains to be seen. |
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| lopaka3 Great Old One Joined: 17 Sep 2001 Total posts: 2154 Location: Near the corner of a Big Continent Gender: Male |
| Posted: 19-05-2005 00:59 Post subject: |
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I'm not trying to sound too nasty towards the hard-working scientists at the US Geological Survey, but I'm having a way hard time taking this at all seriously. Earthquake forecasts. Just like the weather. I don't believe the earth's forces are understood well enough to accurately predict (ahh, not "predict", that's for charlatans...we "forecast".  ) the where and how strong, even with a fair margin of error provided, earthquakes will occur. Just limiting it to aftershocks. And secondly, what is your average Angelino, say, supposed to do with said "forecast" once they get it? Take an umbrella? I mean it's a neat, (if slightly goofy) toy for geophysics geeks that may very well prove to be a valuable tool, but as a public inormation source? 
| Quote: |
California quake forecast goes online
Wednesday, May 18, 2005 Posted: 3:18 PM EDT (1918 GMT)
PASADENA, California (AP) -- California residents wondering if tomorrow's forecast will be sunny now can find out if there's also a chance of afternoon tremors.
For the first time, they can check a daily earthquake forecast on the Internet just as easily as they check the weather.
The Web site, maintained by the U.S. Geological Survey, is updated hourly and calculates the probability of strong ground shaking at specific locations over a 24-hour period. The program is not meant to predict when the "Big One" will occur nor serve as a warning signal for residents to evacuate.
Most of the maps will show that the chances of a significant shaking are pretty slim most of the time. USGS seismologist Matthew Gerstenberger said the site would probably be most useful after a strong temblor that has caused significant damage. Since aftershocks are likely in those situations, residents can log online and check for the possibility of more jolting in their area.
Details appear in Thursday's issue of the journal Nature.
California residents already can view real-time earthquake maps with the click of a mouse, but those are usually posted and updated within minutes of a temblor occurring. Now they can click on real-time, color-coded maps that provide earthquake probabilities in a specific region. Areas shaded in red represent a high chance of strong shaking within the next 24 hours (less than a 1 in 10 chance) while those in blue represent a very remote chance, say, more than 1 in a million.
"If there's a red spot, then make sure you've done what you need to do in terms of earthquake preparedness," Gerstenberger said.
The earthquake forecast maps are created by considering a variety of factors, including monitoring the San Andreas Fault and other active faults in California with seismic instruments. Scientists also factor in any recent history of small and large temblors as well as aftershocks, on those same faults.
In an accompanying commentary, Duncan Agnew of the Scripps Institution of Oceanography at the University of California, San Diego, noted that the latest forecast maps give earthquake victims a "much more precise answer" about the risk of aftershocks after a strong tremor. Agnew, who was not part of the project, also said he would like to see the same method applied to other earthquake-stricken countries around the world.
Copyright 2005 The Associated Press.
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http://www.cnn.com/2005/TECH/science/05/18/earthquake.forecast.ap/index.html |
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| ramonmercado Psycho Punk
Joined: 19 Aug 2003 Total posts: 17933 Location: Dublin Gender: Male |
| Posted: 15-12-2005 12:10 Post subject: |
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| Quote: | Predicting earthquakes
Granite batteries
Dec 14th 2005 | SAN FRANCISCO
From The Economist print edition
Earthquakes may cause electrical surges—which might help predict them
THE inhabitants of San Francisco would dearly like to know when the San Andreas fault that runs by their city is going to snap again. But even after almost 12,000 geophysicists met there last week for the autumn conclave of the American Geophysical Union (AGU), they were little the wiser. Most geophysicists agree that earthquakes cannot be predicted, although every large one brings tales of animals sensing trouble hours beforehand and of people seeing strange lights.
No one knows what might cause such phenomena. Indeed, so many different mechanisms have been proposed as being behind the apparent warnings of impending disaster, that seismologists tend to look upon any claim with suspicion. There is, however, one set of observations that may yet receive a scientific imprimatur. This is the suggestion—yet to be confirmed by an unambiguous statistical analysis—that space-borne instruments such as France's Demeter satellite have seen changes in the radio waves of the ionosphere that coincide with, and sometimes precede, earthquakes in the ground below.
In the light of this suggestion, Friedemann Freund, a physicist at San Jose State University in California, has stuck his neck out. As he told the AGU meeting, he thinks he knows what is going on, and it is this: if you squeeze a block of granite hard enough, it becomes a battery.
If he is right, an earthquake will generate enormous electrical currents in the ground—precisely the sort of thing that would upset the ionosphere and generate strange lights in the form of lightning-related phenomena. More to the point, it is possible that some of this power might be released before a fault moves catastrophically, and thus provide some warning of an earthquake.
The idea that squeezing crystals has electrical consequences is not new. A phenomenon called piezoelectricity, which is exploited in pressure sensors and quartz watches, involves creating a voltage between the ends of a piece of crystal by applying pressure. In this case, the voltage arises because the crystal deforms and a symmetry between positively and negatively charged atoms is disturbed.
Piezoelectricity, however, cannot sustain a sizeable current. So Dr Freund is proposing a different mechanism—similar to the one that goes on in the semiconductors from which computer chips are made. This mechanism relies on another phenomenon, called charge separation.
In many kinds of rock, most notably granite, the application of pressure and the resulting deformation of the rock's constituent crystals turn some of the oxygen atoms in those crystals into charge carriers. These atoms are missing an electron and are thus positively charged.
When the rock is further deformed, it becomes possible for these atoms, called “holes”, to steal an electron from a neighbouring atom, in effect shifting the hole. In this way, the holes can move through the rock. Indeed, they do this so easily, Dr Freund has calculated, that many of them move out of the section of rock under stress altogether, leaving it with a surplus of electrons. Thus, a granite battery is charged.
The electrons from the stressed rock cannot follow the holes, because granite is not a very good conductor of this more usual form of electricity. But when, if you do this trick in a laboratory, you give the electrons the chance to bypass a section of rock by way of a metal wire, quite large currents will flow. Outside the laboratory, Dr Freund believes, the role of the wire is played by heated rock (at temperatures above 500°C, granite becomes conductive to electrons as well as holes).
Extrapolating from Dr Freund's laboratory experiments, the strain in a real-life geological fault such as the San Andreas could, as it shifted, generate hundreds of thousands of amperes per cubic kilometre in a fluctuating pattern that would cause very low frequency radio waves to be emitted, thus disrupting the ionosphere.
Whether such currents could act as earthquake predictors depends on whether there are changes in the strain on a fault before it slips. To date, no such changes have been detected, but Dr Freund argues that the strain gauges deployed at the moment are too near the surface to pick up shifts that happen at the depths where earthquakes occur. His electrical currents, by contrast, would be detectable by magnetometers at the surface as well as by satellites watching the ionosphere—if they do indeed exist in the ground as well as the lab.
http://www.economist.com/science/displayStory.cfm?story_id=5299968 |
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| Rubyait Great Old One Joined: 10 Sep 2004 Total posts: 1783 Location: Not telling Gender: Unknown |
| Posted: 16-12-2005 12:45 Post subject: |
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Ocean floor boring ship may aid quake prediction
| Quote: | A colossal vessel that will drill 7000 metres below the surface of the Earth - in an attempt to collect the first ever samples of the Earth's mantle - has completed its first training mission at sea.
The 57,500-tonne deep-sea drilling ship Chikyu made a port call in Yokohama on Thursday after collecting sub-surface samples, from relatively shallow depths, during its maiden voyage.
The ship will try to take samples from unprecedented depths beneath the seabed and will bore through a "subduction zone" - the point where one tectonic plate descends underneath another. This should provide new data on the seismic activity that produces earthquakes on the surface. But the researchers also hope to detect primitive subsurface organisms known as extremophiles and to find clues to prehistoric climate change.
Chikyu - which means "Earth" in Japanese - is equipped with a 121-metre drill tower capable of boring 7000 metres below the seabed. But it could take more than a year to drill so far down, so the ship will maintain its position above the drill hole using satellite and ocean bed navigation systems and six propellers located beneath its hull.
The deepest hole drilled through the seabed so far reaches 2111 metres. Chikyu will set off in September 2007 to collect the first samples from 7000 metres, at a point some 600 kilometres southwest of Tokyo, Japan.
The project, called the Integrated Ocean Drilling Program (IODP), is led by Japan and the United States with the participation of China and the European Union.
Apollo project
The mantle lies around 30 kilometres below the continental crust, but is much closer to the surface beneath the oceans. Chikyu will insert a "conductor pipe" and a "casing pipe" hundreds of metres into the Earth's crust, to support a thinner drill that will bore thousands of metres down.
"This is like an Apollo project under the Earth," says staff scientist Kan Aoike. "This is a serious attempt to complete another key exploration for mankind."
Asahiko Taira, director-general of the project, said he hoped the project would help scientists predict deadly earthquakes. "For Japan the most important thing is to drill through areas where plates are overlapping so that we can monitor an earthquake directly," he said.
Taira said the seabed off Sumatra in Indonesia, which produced the massive earthquake that triggered the Indian Ocean tsunami in December 2004, could be another potential drilling spot in the future.
http://www.newscientist.com/article.ns?id=dn8470
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| Anonymous |
| Posted: 16-01-2006 18:34 Post subject: |
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Here's another article on that.
| Quote: |
The Times January 16, 2006
Scientists journey towards centre of the Earth to seek out origins of life
From Leo Lewis in Kochi Shinko
THE world’s most technologically advanced exploration ship sails today on a mission that may reveal the origin of life on Earth.
The Japanese ship Chikyu intends to drill seven kilometres (4.3 miles) below the sea bed — more than three times deeper than has been done before. It will then raise to the surface a cylinder 1.5m (5ft) long and 15cm wide which could contain science’s first glimpse of a “living” sample of the Earth’s mantle.
“The 20th century was all about the origin of matter and the universe, so it seemed useful to go to space and the Moon,” the project’s director general, Asahiko Taira, told The Times. “There were extraordinary advances and we learnt about atoms and the Big Bang. The 21st century is about the fundamental question of where life comes from.”
The ship will also be conducting research into the origin of earthquakes. By sinking sensors beneath the Earth’s crust scientists aboard the Chikyu want to provide Japan and East Asia with the first effective earthquake prediction system.
The theory behind the life sciences side of the research is that life may have originated beneath the Earth’s crust at temperatures and pressures unknown on land or sea. The energy that provoked the first semblance of life may also have been geothermal rather than solar.
Samples of mantle that have been pushed to the Earth’s surface over thousands of years have been studied by scientists but nobody has ever seen a “living” slice or had the opportunity to see whatever micro-organisms may be living there.
“This planet is home and we know so little about what is going on just a relatively little distance below our feet. If the secret of life exists to be seen, it is in the deep somewhere,” Dr Taira said.
After completing the training missions that begin today, the ship, which cost about £350 million to build and will cost another £50 million for every year it is drilling, will head to the Nankai Trough, 200 kilometres off the coast of Nagoya, where the sea-bed is 2.5 kilometres below the surface.
The mission of discovery is not restricted to biology. Physical samples of the mantle are also expected to deliver a rich trove of seismological, volcanic, geological, environmental and climatological information. The reason the Japanese project offers the prospect of such important scientific discoveries is not depth alone.
The now-abandoned Russian Kola Well bored nearly 12 kilometres into the Earth, but contributed virtually nothing to science because its entire depth was all in the crust. The Japanese project will be the first to reach the entirely unsurveyed environment of the mantle — the next layer of depth within the Earth — and will do so by exploiting that the Japanese archipelago lies near to a site where main tectonic plates overlap, making it an area where the Earth’s crust is thinner.
By boring beneath the seabed the scientists will take advantage that the Mohorovicic Discontinuity (the point where the crust officially becomes the mantle) is nearer than it is on land.
Although the international project has the financial and scientific involvement of the US, South Korea, several European countries and China, it is led by the Japan Agency for Marine Earth Science and Technology and is heavily funded by the Japanese taxpayer. The cost can be justified because of what the Chikyu may find about the origins of earthquakes.
By drilling to record-breaking depths below areas where tectonic plates overlap, the ship may have its sensors in place as an earthquake begins and significantly advance the science of seismology.
Other areas of research include using deep rock samples to construct a better picture of Earth’s environmental history, particularly in the areas under ice caps, which may offer clues to the baffling question of why the polarity of the planet’s magnetic field has repeatedly switched.
The project’s chief engineer, Kiyotaka Yamamoto, said: “We will be drilling at possible temperatures of 200C (392F), pressures at which we make industrial diamonds and through rock that even the oil industry has never scratched. Of course there will be failures before we get down there, but this is Japan’s Apollo mission.”
A DRILL TOO FAR
# In 1957 the American scientist Walter Munk proposed drilling through to the Earth’s mantle to find out more about the Earth’s origins
# Drilling began in March 1961 off the coast of Guadalupe in Mexico, using a former oil drillship. Five holes were drilled in the sea bed 3,500m below sea level, the deepest reaching 183m into the crust
# The second phase of the project, which would have continued drilling towards the mantle, was abandoned by Congress as too expensive
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http://www.timesonline.co.uk/article/0,,25689-1987747,00.html |
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| Rubyait Great Old One Joined: 10 Sep 2004 Total posts: 1783 Location: Not telling Gender: Unknown |
| Posted: 17-01-2006 10:40 Post subject: |
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| Well good luck to them, we shall see how they do... |
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| ramonmercado Psycho Punk
Joined: 19 Aug 2003 Total posts: 17933 Location: Dublin Gender: Male |
| Posted: 26-09-2008 12:07 Post subject: |
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Stalagmites may predict next Big One along the New Madrid Seismic Zone
| Quote: |
Small white stalagmites lining caves in the Midwest may help scientists chronicle the history of the New Madrid Seismic Zone (NMSZ) – and even predict when the next big earthquake may strike, say researchers at the Illinois State Geological Survey and the University of Illinois at Urbana-Champaign.
While the 1811-12, magnitude 8 New Madrid earthquakes altered the course of the Mississippi River and rung church bells in major cities along the East Coast, records of the seismic zone's previous movements are scarce. Thick layers of sediment have buried the trace of the NMSZ and scientists must search for rare sand blows and liquefaction features, small mounds of liquefied sand that squirt to the surface through fractures during earthquakes, to record past events. That's where the stalagmites come in.
The sand blows are few and far between, said Keith Hackley, an isotope geochemist with the Illinois State Geological Survey. In contrast, caves throughout the region are lined with abundant stalagmites, which could provide a better record of past quakes. "We're trying to see if the initiation of these stalagmites might be fault-induced, recording very large earthquakes that have occurred along the NMSZ," he said.
Hackley and co-workers used U-Th dating techniques to determine the age of stalagmites from Illinois Caverns and Fogelpole Cave in southwestern Illinois. They discovered that some of the young stalagmites began to form at the time of the 1811-12 earthquakes.
Hackley is scheduled to present preliminary results of the study in a poster on Sunday, 5 October, at the 2008 Joint Meeting of the Geological Society of America (GSA), Soil Science Society of America (SSSA), American Society of Agronomy (ASA), Crop Science Society of America (CSSA), and Gulf Coast Association of Geological Societies (GCAGS), in Houston, Texas, USA.
Water slowly trickles through crevices in the ceiling of a cave and drips onto the floor. Each calcium carbonate-loaded drip falls on the last, and a stalagmite slowly grows from the bottom up. Time is typically recorded in alternating light and dark layers – each pair represents a year.
When a large earthquake shakes the ground, old cracks may seal and new ones open. As a result, some groundwater seeping through the cave ceiling traces a new pattern of drips – and, eventually, stalagmites – on the cave floor. Thus it is possible that each new generation of stalagmites records the latest earthquake.
The scientists use fine drills, much like those used by dentists, to burrow into the stalagmites to collect material for dating. In addition to the 1811-12 earthquakes, their investigation has recorded seven historic earthquakes dating as far back as almost 18,000 years before the present. Understanding the NMSZ's past, including whether quakes recur with any regularity, will help the scientists predict the potential timing of future quakes.
In coming months, Hackley and his colleagues plan to expand the study, collecting stalagmites from caves across Indiana, Missouri and Kentucky. They hope that the new data will help to fill in more of the missing history of the NMSZ.
Source: Geological Society of America
http://www.physorg.com/printnews.php?newsid=141569379
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| Ginando Great Old One Joined: 03 Mar 2008 Total posts: 323 Location: Somewhere other than where I really want to be Gender: Male |
| Posted: 27-09-2008 02:52 Post subject: |
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I wish someone had a working predictor, because my wife and I just about soiled our bed when we had an earthquake while on holiday in Rhodes in July. It's the first time we had experienced an earthquake, and it put the fear of God into both of us as we were sure the building was going to fall down 
Infact, come to think of it, do we have any real experts on the subject, because most of us at the complex to whom we spoke experienced stomach cramp type symptoms which I wondered if they were simply nerves, or is it down to Ultra low type frequencies or some similar effect. The thing I found eerie was the noise, a constant but low pitched rumbling sound, almost unearthly. |
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| ramonmercado Psycho Punk
Joined: 19 Aug 2003 Total posts: 17933 Location: Dublin Gender: Male |
| Posted: 27-09-2008 19:49 Post subject: |
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| There was an earthquake in Dublin on 19 July 1984, well it was centred in North Wales. 5.4 on the Richter scale.I had been on the razzle the night before and thought I was having the dts! |
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