Posted: 1/5/2009 3:04 PM
by Travis Larchuk
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All Things Considered, January 3, 2009 · A few little earthquakes here or there is just a part of everyday life when you live on top of the largest supervolcano in North America.
But in the past eight days, there have been more than 400 earthquakes at Yellowstone National Park — where the volcanic system powers the geysers, mud pots and steam vents.
Hank Heasler, a National Park Service geologist at Yellowstone, says the constant quakes haven't caused any damage, but they can be a nuisance to rangers who live at the park.
"They have commented to me that they would appreciate it if the earthquakes would stop so they could get a good night's sleep," he says.
When a bunch of earthquakes occur in a concentrated area in a short amount of time, geologists call it a "swarm." They're not unheard of at Yellowstone, but rarely have the earthquakes reached the magnitude and frequency of the past week.
"Back in 1985, there was an earthquake swarm that lasted for three months and had a magnitude 4.7 earthquake associated with it. The current swarm has had a maximum earthquake of only 3.9," Heasler says.
Scientists don't know why this particular swarm is so intense, but Heasler says there's no need to worry about an imminent volcanic eruption. The last time the supervolcano erupted was 640,000 years ago.
"There will be many months of work after the swarm stops to try to figure out the precise cause of these earthquakes," he says
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"The earthquake sequence is the most intense in this area for some years," said the Yellowstone Volcano Observatory. Some of the larger earthquakes have been felt by park employees and guests, according to the observatory.
The swarm is occurring beneath the northern part of Yellowstone Lake in the park. Yellowstone sits on the caldera of an ancient supervolcano and continuing geothermal activity can be seen in the picturesque geysers and steam holes, such as Old Faithful.
About 1,000 to 2,000 tremors a year have been recorded since 2004. The most devastating earthquake in recent history in the Yellowstone region occurred on August 17, 1959, when a magnitude 7.1 earthquake hit.
It was centered near Hebgen Lake, Montana and it caused landslides that killed 28 people and caused more than $11 million in damage.
Geysers in Yellowstone National park changed eruption times, and new ones began to erupt. On June 30, 1975, a magnitude 6.4 tremor hit the park.
Professor Robert B. Smith, a geophysicist at the University of Utah and one of the leading experts on earthquake and volcanic activity at Yellowstone, said that the swarm was significant.
"It's not business as usual," he said. "This is a large earthquake swarm, and we've recorded several hundred. We are paying careful attention. This is an important sequence."
The last full-scale explosion of the Yellowstone Supervolcano, the Lava Creek eruption which happened approximately 640,000 years ago, ejected about 240 cubic miles of rock and dust into the sky.
Geologists have been closely monitoring the rise and fall of the Yellowstone Plateau as an indication of changes in magma chamber pressure.
The Yellowstone caldera floor has risen recently - almost 3in per year for the past three years - a rate more than three times greater than ever observed since such measurements began in 1923.
From mid-summer 2004 through to mid-summer 2008, the land surface within the caldera moved upwards as much as 8in at the White Lake GPS station. The last major earthquake swarm was in 1985 and lasted three months.
The observatory said similar swarms have occurred in the past without triggering steam explosions or volcanic activity. However, the observatory said there is some potential for explosions and that earthquakes may continue and increase in intensity.
Joe Moore, director of the Wyoming Office of Homeland Security, said his office is tracking the events at Yellowstone on a minute-by-minute basis. "It's being followed very closely," Mr Moore said.
Last edited 1/5/2009 3:23 PM by Matt6999
Posted: 1/5/2009 3:36 PM
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Last edited 1/6/2009 11:06 AM by Matt6999
Posted: 1/6/2009 11:12 AM
Posted: 1/6/2009 12:57 PM
fsafety wrote: one of the best song lines ever....i woke up this morning and got myself a beer, 'cause the futures uncertain, and the end is always near.
Posted: 1/6/2009 1:00 PM
Posted: 1/6/2009 3:34 PM
"Why does stuff that happens to stupid people keep happening to me?"
Posted: 1/6/2009 3:43 PM
fsafety wrote: jim morrison
Posted: 1/6/2009 5:28 PM
Posted: 1/7/2009 1:13 AM
Posted: 1/7/2009 1:52 AM
Posted: 1/7/2009 3:14 AM
Posted: 1/7/2009 6:51 AM
for some reason i have this song stuck in my head
Posted: 1/7/2009 8:30 AM
fellasheowed wrote: now i may be one of the few dual fans of both the smiths and the nfl, but i think there is a conspiracy afoot...
Posted: 1/9/2009 1:45 AM
It's Nostradamus week on the History channel.
Got a question for the science geeks. If Yellowstone blew and even if you had a deep bunker stocked with all the supplies to last for years, wouldn't you still die from carbon dioxide poisoning eventually?
Posted: 1/9/2009 8:45 AM
MountVJackets wrote: It's Nostradamus week on the History channel.Got a question for the science geeks. If Yellowstone blew and even if you had a deep bunker stocked with all the supplies to last for years, wouldn't you still die from carbon dioxide poisoning eventually?
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