perturbed
November-8th-2007, 02:15 PM
http://www.sltrib.com/news/ci_7406215
The floor of the Yellowstone caldera has risen at a rate faster than has ever been observed before, according to a new study that gives further proof that "ground deformation" at the park resembles the gently heaving chest of a slumbering giant.
The likely cause of the uplift is a volcanic intrusion of molten rock that has moved upward 50 to 60 miles and flattened into a pancake the size of Los Angeles a few miles below the surface, according to a study to be published Friday by University of Utah scientists.
Meanwhile, further research is needed to investigate the role hot water and gases play in the mysterious rise and subsidence of Yellowstone, the marquee national park famous for its geothermal features. The new findings in no way should be construed as a harbinger of a natural disaster.
"There is no evidence of an imminent volcanic eruption or hydrothermal explosion. That's the bottom line," said seismologist Robert B. Smith, the study's lead author and a U. professor of geophysics. "A lot of calderas worldwide go up and down over decades without erupting."
Still, the floor of the Yellowstone caldera rose 7 inches during the 30-month study period that concluded at the end of 2006. The 2.8-inch-per-year rate of uplift was much more rapid than had ever been observed since scientists began recording Yellowstone's ground movement in
1923. Previously, the most rapid uplift occurred from 1976 to 1985, when the bulge grew less than an inch a year, according to the article titled, "Accelerated Uplift and Magmatic Intrusion of the Yellowstone Caldera, 2004 to 2006," in the Nov. 9 edition of Science.
"Our best evidence is that the crustal magma chamber is filling with molten rock," Smith said. "But we have no idea how long this process goes on before there either is an eruption or the inflow of molten rock stops and the caldera deflates again."
Yellowstone overlies a "hotspot" in the earth's crust that has produced massive eruptions, at least 140 over the past 16 million years. Hundreds of miles below, scientists believe, is a massive plume of magma that occasionally releases blobs of molten rock that rise and fill the chamber under the Yellowstone caldera.
The floor of the Yellowstone caldera has risen at a rate faster than has ever been observed before, according to a new study that gives further proof that "ground deformation" at the park resembles the gently heaving chest of a slumbering giant.
The likely cause of the uplift is a volcanic intrusion of molten rock that has moved upward 50 to 60 miles and flattened into a pancake the size of Los Angeles a few miles below the surface, according to a study to be published Friday by University of Utah scientists.
Meanwhile, further research is needed to investigate the role hot water and gases play in the mysterious rise and subsidence of Yellowstone, the marquee national park famous for its geothermal features. The new findings in no way should be construed as a harbinger of a natural disaster.
"There is no evidence of an imminent volcanic eruption or hydrothermal explosion. That's the bottom line," said seismologist Robert B. Smith, the study's lead author and a U. professor of geophysics. "A lot of calderas worldwide go up and down over decades without erupting."
Still, the floor of the Yellowstone caldera rose 7 inches during the 30-month study period that concluded at the end of 2006. The 2.8-inch-per-year rate of uplift was much more rapid than had ever been observed since scientists began recording Yellowstone's ground movement in
1923. Previously, the most rapid uplift occurred from 1976 to 1985, when the bulge grew less than an inch a year, according to the article titled, "Accelerated Uplift and Magmatic Intrusion of the Yellowstone Caldera, 2004 to 2006," in the Nov. 9 edition of Science.
"Our best evidence is that the crustal magma chamber is filling with molten rock," Smith said. "But we have no idea how long this process goes on before there either is an eruption or the inflow of molten rock stops and the caldera deflates again."
Yellowstone overlies a "hotspot" in the earth's crust that has produced massive eruptions, at least 140 over the past 16 million years. Hundreds of miles below, scientists believe, is a massive plume of magma that occasionally releases blobs of molten rock that rise and fill the chamber under the Yellowstone caldera.