And this is why I live on the East coast 
Multiple tiny earthquakes rattle Yellowstone. Could the big one be far behind?: Scientific American Blog
Great Indian Ocean Earthquake Of 2004 Set Off Tremors In San Andreas Fault
Yellowstone Caldera - Wikipedia, the free encyclopedia
The Associated Press: Scientists eye unusual swarm of Yellowstone quakes
Multiple tiny earthquakes rattle Yellowstone. Could the big one be far behind?
Any disaster fiend will tell you that Yellowstone National Park is long overdue for a monster eruption that could leave as much as half the U.S. under a blanket of ash. And there are rumblings the big one could be imminent in the wake of a series of 30-plus mini-earthquakes in the park over the past few days?too weak to be felt by humans for the most part but picked up by the seismometers at the University of Utah.
After all, the geologic record shows that the giant caldera we affectionately call Yellowstone has blown every 600,000 years or so over the past 2 million years. The last big eruption? About 640,000 years ago when the park spit out about 240 cubic miles worth of rock, dirt, magma and other stuff.
But don't panic yet. Although the earthquake swarm continues, according to the Yellowstone Volcano Observatory, the volcano alert level remains normal. And a slew of larger earthquakes have occurred throughout the western U.S., Alaska, Puerto Rico and even Pennsylvania in the past week without incident, according to the U.S. Geological Survey.
In recent years, Yellowstone's caldera has been rising thanks to uplifting magma beneath it?leading to more cracks, hot springs and even more frequent eruptions of Steamboat Geysers. Paired with the earthquakes, such magma movement might presage an eruption?either big or small. Unfortunately, scientists can't really predict when the next such eruption will happen, and the range of possibilities is large: from later today to a million years from now.
How will we know if we should start worrying? The real warning signs will be rapid changes in the shape of the ground as well as volcanic gases leaking from the ground, neither of which have been sighted?yet.
"Eruptions are far enough apart that there is a very low probability of the next eruption happening in our lifetimes or anytime soon," Daniel Dzurisin of the USGS told me in 2006. "The flipside is: [Yellowstone] has been active for millions of years and it's going to erupt again sometime."
Credit: ?iStockphoto.com/Steve Geer
Any disaster fiend will tell you that Yellowstone National Park is long overdue for a monster eruption that could leave as much as half the U.S. under a blanket of ash. And there are rumblings the big one could be imminent in the wake of a series of 30-plus mini-earthquakes in the park over the past few days?too weak to be felt by humans for the most part but picked up by the seismometers at the University of Utah.
After all, the geologic record shows that the giant caldera we affectionately call Yellowstone has blown every 600,000 years or so over the past 2 million years. The last big eruption? About 640,000 years ago when the park spit out about 240 cubic miles worth of rock, dirt, magma and other stuff.
But don't panic yet. Although the earthquake swarm continues, according to the Yellowstone Volcano Observatory, the volcano alert level remains normal. And a slew of larger earthquakes have occurred throughout the western U.S., Alaska, Puerto Rico and even Pennsylvania in the past week without incident, according to the U.S. Geological Survey.
In recent years, Yellowstone's caldera has been rising thanks to uplifting magma beneath it?leading to more cracks, hot springs and even more frequent eruptions of Steamboat Geysers. Paired with the earthquakes, such magma movement might presage an eruption?either big or small. Unfortunately, scientists can't really predict when the next such eruption will happen, and the range of possibilities is large: from later today to a million years from now.
How will we know if we should start worrying? The real warning signs will be rapid changes in the shape of the ground as well as volcanic gases leaking from the ground, neither of which have been sighted?yet.
"Eruptions are far enough apart that there is a very low probability of the next eruption happening in our lifetimes or anytime soon," Daniel Dzurisin of the USGS told me in 2006. "The flipside is: [Yellowstone] has been active for millions of years and it's going to erupt again sometime."
Credit: ?iStockphoto.com/Steve Geer
Great Indian Ocean Earthquake Of 2004 Set Off Tremors In San Andreas Fault
ScienceDaily (Dec. 24, 200
? In the last few years there has been a growing number of documented cases in which large earthquakes set off unfelt tremors in earthquake faults hundreds, sometimes even thousands, of miles away.
New research shows that the great Indian Ocean earthquake that struck off the Indonesian island of Sumatra on the day after Christmas in 2004 set off such tremors nearly 9,000 miles away in the San Andreas fault at Parkfield, Calif.
"We found that an earthquake that happened halfway around the world could trigger a seismic signal in the San Andreas fault. It is a low-stress event and a new kind of seismic phenomenon," said Abhijit Ghosh, a University of Washington doctoral student in Earth and space sciences.
"Previous research has shown that this phenomenon, called non-volcanic tremor, was produced in the San Andreas fault in 2002 by the Denali earthquake in Alaska, but seeing this new evidence of tremor triggered by an event as distant as the Sumatra earthquake is really exciting," he said.
Ghosh is to present the findings Dec. 17 in a poster at the American Geophysical Union annual meeting in San Francisco.
The Indian Ocean earthquake on Dec. 26, 2004, was measured at magnitude 9.2 and generated tsunami waves that killed a quarter-million people. It was not known, however, that an earthquake of even that magnitude could set off non-volcanic tremor so far away.
The San Andreas fault in the Parkfield region is one of the most studied seismic areas in the world. It experiences an earthquake of magnitude 6.0 on an average of every 22 years, so a variety of instruments have been deployed to record the seismic activity.
In this case, the scientists examined data from instruments placed in holes bored in the ground as part of the High-Resolution Seismic Network operated by the University of California, Berkeley, as well as information gathered by the Northern California Seismic Network operated by the U.S. Geological Survey.
Signals corresponding with non-volcanic tremor at precisely the time that seismic waves from the Indian Ocean earthquake were passing the Parkfield area were recorded on a number of instruments as far as 125 miles apart.
"It's fairly obvious. There's no question of this tremor being triggered by the seismic waves from Sumatra," Ghosh said.
Scientists have pondered whether non-volcanic tremor is related to actual slippage within an earthquake fault or is caused by the flow of fluids below the Earth's surface. Recent research supports the idea that tremor is caused by fault slippage.
"If the fault is slipping from tremor in one place, it means stress is building up elsewhere on the fault, and that could bring the other area a little closer to a big earthquake," Ghosh said.
Monitoring tremor could help to estimate how much stress has built up within a particular fault.
"If the fault is closer to failure, then even a small amount of added stress likely can produce tremor," he said. "If the fault is already at low stress, then even high-energy waves probably won't produce tremor."
The work adds to the understanding of non-volcanic tremor and what role it might play in releasing or shifting stress within an earthquake-producing fault.
"Our single-biggest finding is that very small stress can trigger tremor," Ghosh said. "Finding tremor can help to track evolution of stress in the fault over space and time, and therefore could have significant implications in seismic hazard analysis."
Co-authors of the poster are John Vidale, Kenneth Creager and Heidi Houston of the UW and Zhigang Peng of the Georgia Institute of Technology. Funding for the work came from the National Science Foundation.
ScienceDaily (Dec. 24, 200
? In the last few years there has been a growing number of documented cases in which large earthquakes set off unfelt tremors in earthquake faults hundreds, sometimes even thousands, of miles away.New research shows that the great Indian Ocean earthquake that struck off the Indonesian island of Sumatra on the day after Christmas in 2004 set off such tremors nearly 9,000 miles away in the San Andreas fault at Parkfield, Calif.
"We found that an earthquake that happened halfway around the world could trigger a seismic signal in the San Andreas fault. It is a low-stress event and a new kind of seismic phenomenon," said Abhijit Ghosh, a University of Washington doctoral student in Earth and space sciences.
"Previous research has shown that this phenomenon, called non-volcanic tremor, was produced in the San Andreas fault in 2002 by the Denali earthquake in Alaska, but seeing this new evidence of tremor triggered by an event as distant as the Sumatra earthquake is really exciting," he said.
Ghosh is to present the findings Dec. 17 in a poster at the American Geophysical Union annual meeting in San Francisco.
The Indian Ocean earthquake on Dec. 26, 2004, was measured at magnitude 9.2 and generated tsunami waves that killed a quarter-million people. It was not known, however, that an earthquake of even that magnitude could set off non-volcanic tremor so far away.
The San Andreas fault in the Parkfield region is one of the most studied seismic areas in the world. It experiences an earthquake of magnitude 6.0 on an average of every 22 years, so a variety of instruments have been deployed to record the seismic activity.
In this case, the scientists examined data from instruments placed in holes bored in the ground as part of the High-Resolution Seismic Network operated by the University of California, Berkeley, as well as information gathered by the Northern California Seismic Network operated by the U.S. Geological Survey.
Signals corresponding with non-volcanic tremor at precisely the time that seismic waves from the Indian Ocean earthquake were passing the Parkfield area were recorded on a number of instruments as far as 125 miles apart.
"It's fairly obvious. There's no question of this tremor being triggered by the seismic waves from Sumatra," Ghosh said.
Scientists have pondered whether non-volcanic tremor is related to actual slippage within an earthquake fault or is caused by the flow of fluids below the Earth's surface. Recent research supports the idea that tremor is caused by fault slippage.
"If the fault is slipping from tremor in one place, it means stress is building up elsewhere on the fault, and that could bring the other area a little closer to a big earthquake," Ghosh said.
Monitoring tremor could help to estimate how much stress has built up within a particular fault.
"If the fault is closer to failure, then even a small amount of added stress likely can produce tremor," he said. "If the fault is already at low stress, then even high-energy waves probably won't produce tremor."
The work adds to the understanding of non-volcanic tremor and what role it might play in releasing or shifting stress within an earthquake-producing fault.
"Our single-biggest finding is that very small stress can trigger tremor," Ghosh said. "Finding tremor can help to track evolution of stress in the fault over space and time, and therefore could have significant implications in seismic hazard analysis."
Co-authors of the poster are John Vidale, Kenneth Creager and Heidi Houston of the UW and Zhigang Peng of the Georgia Institute of Technology. Funding for the work came from the National Science Foundation.
Yellowstone Caldera - Wikipedia, the free encyclopedia
Scientists eye unusual swarm of Yellowstone quakes
By MEAD GRUVER ? 1 day ago
CHEYENNE, Wyo. (AP) ? Yellowstone National Park was jostled by a host of small earthquakes for a third straight day Monday, and scientists watched closely to see whether the more than 250 tremors were a sign of something bigger to come. Swarms of small earthquakes happen frequently in Yellowstone, but it's very unusual for so many earthquakes to happen over several days, said Robert Smith, a professor of geophysics at the University of Utah.
"They're certainly not normal," Smith said. "We haven't had earthquakes in this energy or extent in many years."
Smith directs the Yellowstone Seismic Network, which operates seismic stations around the park. He said the quakes have ranged in strength from barely detectable to one of magnitude 3.8 that happened Saturday. A magnitude 4 quake is capable of producing moderate damage.
"This is an active volcanic and tectonic area, and these are the kinds of things we have to pay attention to," Smith said. "We might be seeing something precursory.
"Could it develop into a bigger fault or something related to hydrothermal activity? We don't know. That's what we're there to do, to monitor it for public safety."
The strongest of dozens of tremors Monday was a magnitude 3.3 quake shortly after noon. All the quakes were centered beneath the northwest end of Yellowstone Lake.
A park ranger based at the north end of the lake reported feeling nine quakes over a 24-hour period over the weekend, according to park spokeswoman Stacy Vallie. No damage was reported.
"There doesn't seem to be anything to be alarmed about," Vallie said.
Smith said it's difficult to say what might be causing the tremors. He pointed out that Yellowstone is the caldera of a volcano that last erupted 70,000 years ago.
He said Yellowstone remains very geologically active ? and its famous geysers and hot springs are a reminder that a pool of magma still exists five to 10 miles underground.
"That's just the surface manifestation of the enormous amount of heat that's being released through the system," he said.
Yellowstone has had significant earthquakes as well as minor ones in recent decades. In 1959, a magnitude 7.5 quake near Hebgen Lake just west of the park triggered a landslide that killed 28 people.
By MEAD GRUVER ? 1 day ago
CHEYENNE, Wyo. (AP) ? Yellowstone National Park was jostled by a host of small earthquakes for a third straight day Monday, and scientists watched closely to see whether the more than 250 tremors were a sign of something bigger to come. Swarms of small earthquakes happen frequently in Yellowstone, but it's very unusual for so many earthquakes to happen over several days, said Robert Smith, a professor of geophysics at the University of Utah.
"They're certainly not normal," Smith said. "We haven't had earthquakes in this energy or extent in many years."
Smith directs the Yellowstone Seismic Network, which operates seismic stations around the park. He said the quakes have ranged in strength from barely detectable to one of magnitude 3.8 that happened Saturday. A magnitude 4 quake is capable of producing moderate damage.
"This is an active volcanic and tectonic area, and these are the kinds of things we have to pay attention to," Smith said. "We might be seeing something precursory.
"Could it develop into a bigger fault or something related to hydrothermal activity? We don't know. That's what we're there to do, to monitor it for public safety."
The strongest of dozens of tremors Monday was a magnitude 3.3 quake shortly after noon. All the quakes were centered beneath the northwest end of Yellowstone Lake.
A park ranger based at the north end of the lake reported feeling nine quakes over a 24-hour period over the weekend, according to park spokeswoman Stacy Vallie. No damage was reported.
"There doesn't seem to be anything to be alarmed about," Vallie said.
Smith said it's difficult to say what might be causing the tremors. He pointed out that Yellowstone is the caldera of a volcano that last erupted 70,000 years ago.
He said Yellowstone remains very geologically active ? and its famous geysers and hot springs are a reminder that a pool of magma still exists five to 10 miles underground.
"That's just the surface manifestation of the enormous amount of heat that's being released through the system," he said.
Yellowstone has had significant earthquakes as well as minor ones in recent decades. In 1959, a magnitude 7.5 quake near Hebgen Lake just west of the park triggered a landslide that killed 28 people.
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