Devices will measure miniscule movements on Mount St. Helens
By Richard L. Hill, The Oregonian
Scientists soon will be getting more detailed clues about what's happening beneath fidgety Mount St. Helens with 17 new instruments being placed around the volcano in the next few weeks.
The sensors -- four deep-hole strainmeters, four tiltmeters and nine global positioning stations -- will be linked to a national network that detects the most subtle movement in the earth's crust. The hope is that these tools -- one of them measures a ground shift as tiny as four-hundreds of an inch in a 620-mile-wide area -- will unlock the secret processes underlying the restless volcano.
Mount St. Helens began signaling its current nonstop eruption with hundreds of earthquakes two years ago today.
"Knowing more about a volcano's underlying mechanisms eventually could lead to techniques for predicting when eruptions will occur," said Sarah Venator, a geologist and engineer with the Plate Boundary Observatory, which is installing the instruments
Venator and other engineers with the national observatory on Friday finished drilling an 800-foot hole near the Windy Ridge viewpoint about three miles northeast of the volcano's crater. Today, they will lower a sensitive strainmeter into the 6-inch-wide hole. The device detects ground deformation at extraordinarily small levels.
An earthquake-detecting seismometer also will be placed in the hole, and a GPS station will detect ground movements at the surface.
"The movement detected by the instruments will give researchers an understanding of how that relates to the movement of magma under the volcano," said Katrin Hafner, regional engineer with the Plate Boundary Observatory. As magma moves up in a volcano, the surrounding ground is strained by the added pressure.
Four of the strainmeters will be placed around the volcano, which will help scientists better understand what's happening in the volcano's plumbing system, especially the magma chamber about four miles beneath the crater.
Data from the instruments will be transmitted continuously to the observatory's headquarters in Boulder, Colo., where it will be accessible to all scientists.
"These new instruments are going to be an important enhancement to our monitoring efforts. They'll fill in some gaps," said Evelyn Roeloffs, a scientist with the Cascades Volcano Observatory in Vancouver, which keeps track of Mount St. Helens. "These won't be a magic bullet to let us predict eruptions right away, but they will give us a better understanding of the processes that are occurring three or four miles beneath the surface."
Though Mt. St. Helens is one of the world's most studied volcanoes with more than 50 instruments tracking its activity, it and other volcanoes aren't the primary target of the Plate Boundary Observatory, a component of the federally funded EarthScope project that is blanketing the United States with seismometers and other motion detectors.
The observatory is placing 103 strainmeters and 852 GPS receivers across the West to take a better look at the North American tectonic plate and where it grinds against the ocean tectonic plates, including the Juan de Fuca Plate off Oregon and Washington. Huge earthquakes have occurred where the two plates move past each other off the coasts, and scientists are concerned that a future earthquake could devastate the Northwest.
Oregon and Washington will have 126 new GPS stations in place in the next two years.
"They will answer a lot of questions about what's going on beneath us," Venator said.
Scientists soon will be getting more detailed clues about what's happening beneath fidgety Mount St. Helens with 17 new instruments being placed around the volcano in the next few weeks.
The sensors -- four deep-hole strainmeters, four tiltmeters and nine global positioning stations -- will be linked to a national network that detects the most subtle movement in the earth's crust. The hope is that these tools -- one of them measures a ground shift as tiny as four-hundreds of an inch in a 620-mile-wide area -- will unlock the secret processes underlying the restless volcano.
Mount St. Helens began signaling its current nonstop eruption with hundreds of earthquakes two years ago today.
"Knowing more about a volcano's underlying mechanisms eventually could lead to techniques for predicting when eruptions will occur," said Sarah Venator, a geologist and engineer with the Plate Boundary Observatory, which is installing the instruments
Venator and other engineers with the national observatory on Friday finished drilling an 800-foot hole near the Windy Ridge viewpoint about three miles northeast of the volcano's crater. Today, they will lower a sensitive strainmeter into the 6-inch-wide hole. The device detects ground deformation at extraordinarily small levels.
An earthquake-detecting seismometer also will be placed in the hole, and a GPS station will detect ground movements at the surface.
"The movement detected by the instruments will give researchers an understanding of how that relates to the movement of magma under the volcano," said Katrin Hafner, regional engineer with the Plate Boundary Observatory. As magma moves up in a volcano, the surrounding ground is strained by the added pressure.
Four of the strainmeters will be placed around the volcano, which will help scientists better understand what's happening in the volcano's plumbing system, especially the magma chamber about four miles beneath the crater.
Data from the instruments will be transmitted continuously to the observatory's headquarters in Boulder, Colo., where it will be accessible to all scientists.
"These new instruments are going to be an important enhancement to our monitoring efforts. They'll fill in some gaps," said Evelyn Roeloffs, a scientist with the Cascades Volcano Observatory in Vancouver, which keeps track of Mount St. Helens. "These won't be a magic bullet to let us predict eruptions right away, but they will give us a better understanding of the processes that are occurring three or four miles beneath the surface."
Though Mt. St. Helens is one of the world's most studied volcanoes with more than 50 instruments tracking its activity, it and other volcanoes aren't the primary target of the Plate Boundary Observatory, a component of the federally funded EarthScope project that is blanketing the United States with seismometers and other motion detectors.
The observatory is placing 103 strainmeters and 852 GPS receivers across the West to take a better look at the North American tectonic plate and where it grinds against the ocean tectonic plates, including the Juan de Fuca Plate off Oregon and Washington. Huge earthquakes have occurred where the two plates move past each other off the coasts, and scientists are concerned that a future earthquake could devastate the Northwest.
Oregon and Washington will have 126 new GPS stations in place in the next two years.
"They will answer a lot of questions about what's going on beneath us," Venator said.
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