Archive | Earthquakes

Study: Pacific Earthquake Was Really Three

SALT LAKE CITY, Aug. 18 (UPI) — Researchers say a deadly 2009 earthquake in the South Pacific was actually three tremors, with the largest hiding the immediate evidence of two smaller ones.

Scientists at the University of Utah say the 8.1 “great earthquake” in September 2009 that killed 192 people in Samoa, American Samoa and Tonga triggered two subsequent 7.8 temblors, a university release said Wednesday.

“At first, we thought it was one earthquake,” study co-author Keith Koper, director of the school’s seismograph stations, said.

“When we looked at the data, it turned out it wasn’t just one great earthquake, but three large earthquakes that happened within two minutes of one another.”

The quakes generated tsunami waves more than 49 feet above sea level in some places that killed at least 149 people in Samoa, 34 people in American Samoa and nine on Niuatoputapu, an island in the northern part of Tonga.

“The two quakes that were hidden by the first quake ended up being responsible for some of the damage and tsunami waves,” Koper said.

In terms of energy release, the two magnitude-7.8 quakes combined “represent the energy release of another magnitude-8 quake,” Koper, an associate professor of geology, said.

“It was essentially a great earthquake that was triggered. It was not some silly little aftershock.”

Copyright 2010 United Press International, Inc. (UPI). Any reproduction, republication, redistribution and/or modification of any UPI content is expressly prohibited without UPI’s prior written consent.

Posted in Earthquakes, Other0 Comments

New Research Examines Midwest Earthquakes

WEST LAFAYETTE, Ind., July 30 (UPI) — U.S. researchers say a new theory may explain how an earthquake fault in the middle of the continent produces large temblors far from a tectonic plate boundary.

Purdue University researchers say energy that produced 7 to 7.5 magnitude quakes in the 1800s on the 150-mile New Madrid fault system that stretches south from Cairo, Ill., through Missouri, Arkansas and Tennessee came from stresses built up in the Earth’s crust long ago, a university release said Friday.

Rapid erosion from the Mississippi River at the end of the last ice age washed away sediment and removed weight pressing down on the Earth’s crust, allowing the fault to slip and trigger earthquakes, they suggest.

The theory could explain how the fault generated large earthquakes in the recent past but today show no signs of accumulating the forces needed to produce another earthquake, Purdue Professor Andrew Freed says.

“The only way to reconcile the fact that this part of the continent is not deforming but is producing earthquakes is for the stresses to have built up long ago,” Freed said.

“Old geologic processes, such as the opening of the Atlantic and the uplift of the Rocky Mountains, may have squeezed the Midwest,” he said.

“The resulting stress remained stored for millions of years until uplift associated with the Mississippi erosion event led to the unclamping of old faults lying beneath.”

Copyright 2010 United Press International, Inc. (UPI). Any reproduction, republication, redistribution and/or modification of any UPI content is expressly prohibited without UPI’s prior written consent.

Posted in Earthquakes, Other0 Comments

Researchers Seek Railway Hazard Warnings

TEL AVIV, Israel, July 27 (UPI) — Israeli researchers say they are developing an early warning hazard system to protect the world’s railways from accidents and even terrorist actions.

Tel Aviv University scientists are collecting high-tech sensing data from satellites, airplanes, ground sensors and unmanned aircraft to devise a solution to provide a reliable early warning system for train operators, a university release said Monday.

The research aims to connect several technologies so train accidents caused by avalanches, earthquakes and even terrorist sabotage can be avoided, Prof. Lev V. Eppelbaum of the school’s Department of Geophysics & Planetary Sciences said.

“Sinkholes, avalanches, landslides, earthquakes, flash floods — these disasters can cause train wrecks anywhere around the world,” says Eppelbaum. “We are hoping to develop a platform that can be fitted to any railway, passenger or freight carrier, to better predict natural disasters and possible terror attacks on rail lines.”

At present, there is no worldwide monitoring system for either natural disasters or terror attacks on rail systems, Eppelbaum said.

The Tel Aviv research is one part of a European project that includes participants from Israel, Italy, France, Sweden, Norway, Switzerland and Romania.

“We are creating a new interpretation system allowing us to integrate cutting-edge technologies from across Europe,” he said.

Copyright 2010 United Press International, Inc. (UPI). Any reproduction, republication, redistribution and/or modification of any UPI content is expressly prohibited without UPI’s prior written consent.

Posted in Earthquakes, Natural Disasters, Other0 Comments

'Doughnut Hole' Quake Theory Studied

LOS ANGELES, July 19 (UPI) — A new earthquake theory suggests doughnut-shaped patterns of temblors build up over decades to a final large earthquake in the doughnut “hole,” scientists say.

The circular pattern theory, called a Mogi doughnut after the Japanese seismologist who proposed it, may lead to improved earthquake forecasts, the Los Angeles Times reported Sunday.

Recent earthquakes near Eureka and Palm Springs in California and Mexicali in Mexico, combined with large seismic upheavals like the 1989 Loma Prieta and 1994 Northridge temblors, could be precursors to a far larger rupture somewhere in the doughnut “hole,” University of California, Davis physicist and geologist John Rundle and his colleagues say.

They just don’t know exactly where or when, the Times reported.

In the past, experts say, little attention was paid to how faults were connected or whether one earthquake could increase the chances of a quake on another fault.

But now they believe these connections are important and this year’s earthquakes along the Mexican border and near Palm Springs are evidence of the concept.

“Previously we would identify a fault, map it and name it,” Lisa Grant Ludwig, a University of California, Irvine earthquake expert, said. “What we’ve really got here is a network of faults. Maybe that’s what we need to be thinking: more big-picture.”

Copyright 2010 United Press International, Inc. (UPI). Any reproduction, republication, redistribution and/or modification of any UPI content is expressly prohibited without UPI’s prior written consent.

Posted in Earthquakes, Other0 Comments

Tiny Clays Curb Big Earthquakes

ANN ARBOR, Mich., June 24 (UPI) — A U.S.-German team of geologists says it has determined why some areas of the San Andreas fault experience repeated earthquakes and other areas do not.

Professor Ben van der Pluijm at the University of Michigan and Professor Laurence Warr of Ernst-Moritz-Arndt University in Greifswald, Germany, said the famously violent fault also has quieter sections where rocks easily slide against each other without giving rise to damaging quakes.

The researchers said they discovered that the smooth movement, called creep, occurs because the fault creates its own lubricants — slippery clays that form ultra-thin coatings on rock fragments.

The question of what causes creep has long puzzled scientists. Some have speculated fluids facilitate slippage, while others have focused on serpentine — a greenish material that can become a kind of slippery talc.

But when van der Pluijm and colleagues analyzed samples of rock from an actively creeping fault two miles deep they found very little talc. Instead, they found fractured rock surfaces coated with a thin layer of smectitic clay, less than 100 nanometers thick, that acts as a lubricant.

“For a long time, people thought you needed a lot of lubricant for creep to occur,” van der Pluijm said. “What we can show is that you don’t really need a lot. It just needs to be in the right place.”

The study that included assistant research scientist Anja Schleicher appears in the July issue of the journal Geology.

Copyright 2010 United Press International, Inc. (UPI). Any reproduction, republication, redistribution and/or modification of any UPI content is expressly prohibited without UPI’s prior written consent.

Posted in Earthquakes, Other0 Comments

Study Finds Synchronicity in Earthquakes

NEW YORK, June 22 (UPI) — A U.S. seismologist says he’s determined earthquakes can occur in synchrony, with big quakes triggering other big quakes along the same fault.

Columbia University Professor Christopher Scholz, a seismologist at the school’s Lamont-Doherty Earth Observatory, says in nature, random signals often fall mysteriously in step — fireflies flashing sporadically in early evening soon flash together, and the same harmonic behavior can be seen in chirping crickets, firing neurons, swinging clock pendulums and now, rupturing earthquake faults.

Scholz says when a fault breaks it might sometimes gently prod a neighboring fault also on the verge of fracturing. He finds evidence for synchronized, or “phase locked,” faults in southern California’s Mojave Desert, the mountains of central Nevada and the south of Iceland.

He identifies strings of related earthquakes, and explains the physics of how faults, separated by up to more than 30 miles and rupturing every few thousand years, might align themselves to rupture nearly simultaneously.

“All of a sudden bang, bang, bang, a whole bunch of faults break at the same time,” Scholz said. “Now that we know that some faults may act in consort, our basic concept of seismic hazard changes. When a large earthquake happens, it may no longer mean that the immediate future risk is lower, but higher.”

He details his findings in the Bulletin of the Seismological Society of America.

Copyright 2010 United Press International, Inc. (UPI). Any reproduction, republication, redistribution and/or modification of any UPI content is expressly prohibited without UPI’s prior written consent.

Posted in Earthquakes, Other0 Comments

NASA Demos Tsunami Prediction System

PASADENA, Calif., June 14 (UPI) — A NASA-led research team says it has successfully demonstrated for the first time elements of a prototype tsunami prediction system.

Scientists at NASA’s Jet Propulsion Laboratory, which manages the system, say it can quickly and accurately assesses large earthquakes and estimate the size of a resulting tsunami.

After February’s magnitude 8.8 Chilean earthquake, a JPL team led by Y. Tony Song used real-time data from the agency’s Global Differential GPS network to successfully predict the size of the resulting tsunami.

Researchers said the network combines global and regional real-time data from hundreds of GPS sites to detect ground motions as small as a few centimeters.

“This successful test demonstrates coastal GPS systems can effectively be used to predict the size of tsunamis,” Song said “This could allow responsible agencies to issue better warnings that can save lives and reduce false alarms that can unnecessarily disturb the lives of coastal residents.”

Song’s prediction method estimates the energy an undersea earthquake transfers to the ocean to generate a tsunami. Scientists said it relies on data from coastal GPS stations near an epicenter, along with information about the local continental slope — the descent of the ocean floor from the edge of the continental shelf to the ocean bottom.

Conventional tsunami warning systems rely on estimates of an earthquake’s location, depth and magnitude. However, researchers say history has shown earthquake magnitude isn’t a reliable indicator of tsunami size.

Copyright 2010 United Press International, Inc. (UPI). Any reproduction, republication, redistribution and/or modification of any UPI content is expressly prohibited without UPI’s prior written consent.

Posted in Earthquakes, Other0 Comments

Giant Quake Possible in Pacific Northwest

CORVALLIS, Ore., May 27 (UPI) — A U.S. scientist says there’s a more than one-in-three chance a major earthquake like the one that struck Chile this year could strike the Pacific Northwest.

Oregon State University Associate Professor Chris Goldfinger, a marine geologist, said he and his colleagues have analyzed the U.S. Northwest’s seismic history, which includes 41 magnitude 8.2 or higher earthquakes during the past 10,000 years.

“Perhaps more striking than the probability numbers is that we can now say that we have already gone longer without an earthquake than 75 percent of the known times between earthquakes in the last 10,000 years,” Goldfinger said.

The last major earthquake to hit the Cascadia Subduction Zone was in January 1700, and scientists are aware of the impact because of written records from Japan documenting the damage caused by an ensuing 30-foot tsunami. Their knowledge about what happened in Oregon and Washington is more speculative, but he said the consensus is that the physical alteration to the coast was stunning.

Goldfinger says the Pacific Northwest is at risk for an earthquake that could meet or exceed the power of seismic events that took place in Chile, as well as Haiti.

“It is not a question of if a major earthquake will strike, it is a matter of when,” Goldfinger said. “And the ‘when’ is looking like it may not be that far in the future.”

Copyright 2010 United Press International, Inc. (UPI). Any reproduction, republication, redistribution and/or modification of any UPI content is expressly prohibited without UPI’s prior written consent.

Posted in Earthquakes, Other0 Comments

New Madrid Quakes Weaker Than Thought

PASADENA, Calif., May 17 (UPI) — Earthquakes that rumbled in the U.S. midsection nearly 200 years ago weren’t nearly as powerful as previously thought, an expert says.

Susan Hough, a seismologist with the U.S. Geological Survey, says the three main temblors associated with the New Madrid quakes of 1811-12 registered no more than a 7-magnitude, not the 7.7 that had been the standard estimate. That means the quakes, which made the Mississippi River flow south to north and created Tennessee’s Reelfoot Lake were only 1/20th as powerful as thought, The (Memphis) Commercial Appeal reported Monday.

Hough presented her findings at a meeting of the Seismological Society of America last month in Portland, Ore.

Since there were no measuring instruments at the time of the quakes, Hough had a team of international experts independently assign “intensity values” to historical accounts of the quakes. That information was then submitted to computer analysis.

“When you do that, across the board the magnitudes are lower,” said Hough, who is based in Pasadena, Calif.

Chris Cramer, a research associate professor with the Center for Earthquake Research and Information at the University of Memphis, questioned the accuracy of magnitudes based on the historical accounts, the newspaper reported.

“There is a little bit of a disconnect,” Cramer said. “Scientifically, you cannot say what she is stating is true.”

Copyright 2010 United Press International, Inc. (UPI). Any reproduction, republication, redistribution and/or modification of any UPI content is expressly prohibited without UPI’s prior written consent.

Posted in Earthquakes, Other0 Comments

USGS to Fund Earthquake Monitoring

WASHINGTON, May 4 (UPI) — The U.S. Geological Survey says it plans to award more than $7 million this year in cooperative agreements for earthquake monitoring.

USGS officials said the funding will contribute to the development and operation of its Advanced National Seismic System.

“Earthquake monitoring is absolutely critical to providing fast information to emergency-response personnel in areas affected by earthquakes, so by building and repairing those monitoring systems, these cooperative agreements literally save lives and property,” Secretary of the Interior Ken Salazar said.

USGS officials said the funding will help provide continuous, real-time monitoring of earthquake activity and the collection of critical information about how earthquake shaking affects buildings and structures. Funds are also being provided for the operation of geodetic monitoring networks that detect minute changes in the Earth’s crust caused by faulting in earthquake-prone regions, officials said.

Institutions receiving funding are the California Institute of Technology; the Universities of Washington, Utah, California-Berkeley, Memphis, Alaska-Fairbanks, Nevada-Reno, California-San Diego, South Carolina, Oregon, and Colorado; Columbia University; St. Louis University; Boston College; the Montana Bureau of Mines and Geology at the University of Montana; Central Washington University; and San Francisco State University.

Copyright 2010 United Press International, Inc. (UPI). Any reproduction, republication, redistribution and/or modification of any UPI content is expressly prohibited without UPI’s prior written consent.

Posted in Buildings, Earthquakes, Other0 Comments

No Posts in Category
Advertisement