Harveylives
11-26-2003, 04:20 PM
Bulging earth under Yellowstone Lake raises fears
By David Kelly
Los Angeles Times
YELLOWSTONE NATIONAL PARK, Wyo. -- Below the blue waters of Yellowstone Lake, a mysterious dome 2,100 feet across and 100 feet high is causing concern among scientists and citizens who don't know whether it's a harmless curiosity or a hazard on the verge of exploding.
The dome, also called a bulge, is less than a mile from shore and was recently explored by researchers with the U.S. Geological Survey, using unmanned submarines and sonar.
"It could be the precursor to a hydrothermal explosion," said Lisa Morgan, a geologist leading the team.
Hydrothermal blasts occur when super-heated water, often under extreme pressure, rapidly flashes to steam, hurling rocks and sometimes gouging out huge craters.
News of the dome comes at a time of increased activity beneath Yellowstone, which experienced a magnitude 4.4 earthquake in August.
In July, the park shut down part of a popular trail near the Norris Geyser Basin because the ground heated up to 200 degrees.
The events have sparked Internet chatter and fear from some that a catastrophe is at hand.
But scientists and park officials have cautioned against panic, saying that Yellowstone is intensely monitored for any changes.
Morgan said while the dome may explode, it might just as easily collapse or simply do nothing.
Still, she and park officials are drawing up a hazard-assessment plan just in case.
"A hydrothermal explosion is an extreme event and a rare event but they have happened," Morgan said.
Mary Bay, an area of the lake near the dome, was created by a hydrothermal blast more than 13,000 years ago that scientists consider to be one of the biggest explosions in geologic history. There are at least five other craters in Yellowstone Lake caused by enormous eruptions.
Exactly what damage an explosion would cause today is being investigated. Morgan said it could eject rocks and poisonous gas and cause waves as high as 20 feet. Whether the damage would spread beyond the park depends on the force of the blast.
"No one has ever witnessed a large hydrothermal explosion. It's a steam explosion, which can be as powerful as TNT," park geologist Hank Heasler said.
Heasler keeps tabs on the rising temperatures in the park through a network of sensors.
The park, which draws 3 million visitors a year, sits atop one of the most active volcanoes on Earth, a deep caldera 45 miles long and 30 miles across, with more than 10,000 vents, geysers and bubbling pools of hot water.
Scientists compare the place to a piecrust expanding with steam then subsiding as heat escapes through the crust.
Geologists estimate that the last big eruption happened 640,000 years ago, when the volcano sent ash as far south as Texas. Scientists say it was 1,000 times more powerful than the Mount Saint Helens cataclysm in 1980. There have been 30 eruptions since.
The lake floor remained largely a mystery until researchers using cameras on robot submarines began exploring it.
Down among the shadows, the team saw more than 250 thermal vents, fissures, geyser basins and columns of silica soaring 30 feet high.
"Everyone is paying attention to the bulge, but it's only one feature," said Morgan, who has studied the lake for five years. "We found extensive fault systems and landslides. When you think of all the seismic energy that could be released, it could be extreme."
A Web site claims Yellowstone "will blow its cork" in the next six months, causing "the three days of darkness spoken of in the Bible."
Such talk confounds park officials and scientists.
"We say the park is safe," said Yellowstone spokeswoman Cheryl Matthews.
By David Kelly
Los Angeles Times
YELLOWSTONE NATIONAL PARK, Wyo. -- Below the blue waters of Yellowstone Lake, a mysterious dome 2,100 feet across and 100 feet high is causing concern among scientists and citizens who don't know whether it's a harmless curiosity or a hazard on the verge of exploding.
The dome, also called a bulge, is less than a mile from shore and was recently explored by researchers with the U.S. Geological Survey, using unmanned submarines and sonar.
"It could be the precursor to a hydrothermal explosion," said Lisa Morgan, a geologist leading the team.
Hydrothermal blasts occur when super-heated water, often under extreme pressure, rapidly flashes to steam, hurling rocks and sometimes gouging out huge craters.
News of the dome comes at a time of increased activity beneath Yellowstone, which experienced a magnitude 4.4 earthquake in August.
In July, the park shut down part of a popular trail near the Norris Geyser Basin because the ground heated up to 200 degrees.
The events have sparked Internet chatter and fear from some that a catastrophe is at hand.
But scientists and park officials have cautioned against panic, saying that Yellowstone is intensely monitored for any changes.
Morgan said while the dome may explode, it might just as easily collapse or simply do nothing.
Still, she and park officials are drawing up a hazard-assessment plan just in case.
"A hydrothermal explosion is an extreme event and a rare event but they have happened," Morgan said.
Mary Bay, an area of the lake near the dome, was created by a hydrothermal blast more than 13,000 years ago that scientists consider to be one of the biggest explosions in geologic history. There are at least five other craters in Yellowstone Lake caused by enormous eruptions.
Exactly what damage an explosion would cause today is being investigated. Morgan said it could eject rocks and poisonous gas and cause waves as high as 20 feet. Whether the damage would spread beyond the park depends on the force of the blast.
"No one has ever witnessed a large hydrothermal explosion. It's a steam explosion, which can be as powerful as TNT," park geologist Hank Heasler said.
Heasler keeps tabs on the rising temperatures in the park through a network of sensors.
The park, which draws 3 million visitors a year, sits atop one of the most active volcanoes on Earth, a deep caldera 45 miles long and 30 miles across, with more than 10,000 vents, geysers and bubbling pools of hot water.
Scientists compare the place to a piecrust expanding with steam then subsiding as heat escapes through the crust.
Geologists estimate that the last big eruption happened 640,000 years ago, when the volcano sent ash as far south as Texas. Scientists say it was 1,000 times more powerful than the Mount Saint Helens cataclysm in 1980. There have been 30 eruptions since.
The lake floor remained largely a mystery until researchers using cameras on robot submarines began exploring it.
Down among the shadows, the team saw more than 250 thermal vents, fissures, geyser basins and columns of silica soaring 30 feet high.
"Everyone is paying attention to the bulge, but it's only one feature," said Morgan, who has studied the lake for five years. "We found extensive fault systems and landslides. When you think of all the seismic energy that could be released, it could be extreme."
A Web site claims Yellowstone "will blow its cork" in the next six months, causing "the three days of darkness spoken of in the Bible."
Such talk confounds park officials and scientists.
"We say the park is safe," said Yellowstone spokeswoman Cheryl Matthews.