|
|
|
|
|
|
|
Scientists Seek Source Of Mount St. Helens Blast
VANCOUVER, Washington (CNN) -- Scientists want to peer inside the crater of Mount St. Helens on Wednesday to locate the origins of a plume of ash and steam that spewed nearly seven miles high into the air Tuesday night.
Geologists cautioned the explosion wasn't necessarily a harbinger of a larger or more destructive eruption.
The U.S. Geological Survey in Vancouver began a 24-hour volcano watch after the eruption at 5:20 p.m. (8:20 p.m. ET). Nearly five hours later, the plume remained visible in satellite photos.
Glowing tendrils of lava were spotted inside the mountain's crater following the explosion. Although the plume rose nearly twice as high as one produced by the last eruption in October, the geological agency classified the event as "small," according to an advisory on the Web site of its Cascades Volcano Observatory.
No damage or injuries were reported. Some air traffic had to be routed around the plume as it rose to 36,000 feet.
The ash remained in the air over Montana on Wednesday and was visible for more than 50 miles (80 kilometers), prompting some motorists to stop their cars and watch.
Scientists waited for daylight Wednesday to use a surveillance helicopter to fly over the mountain's crater and determine the plume's origins.
Although the geological agency has instruments in place to measure volcanic activity, five of the seven monitoring stations in the crater stopped transmitting after the blast. They were likely damaged.
Mount St. Helens, about 45 miles (72 kilometers) east of Vancouver, has been rumbling and spewing steam since September. Scientists said Tuesday's event was to be expected, given the volcano's eruption cycle.
Geologists said activity points to an explosive eruption, though none said they believe it will reach the intensity of the 1980 blast that killed 57 people and knocked more than 1,000 feet off the top of the mountain.
The 1980 eruption created the mountain's current crater. A new lava dome has been forming inside that crater for several months, and the geological agency reported Tuesday that the growth will be accompanied by low-level tremors and emissions of steam, volcanic gases and ash.
"This is clearly part of the ongoing activity which we said can occur and can occur without warning," said a Dan Dzurisin, a spokesman for the geological agency.
Penelope Cassidy, a spokeswoman for the Washington State Emergency Operations Center at Camp Murray, said only essential staff was on duty there. The center is outside Tacoma, more than 80 miles (129 kilometers) north of Mount St. Helens.
"We're monitoring the situation as we have since late September," Cassidy said. "It's just part of the ongoing shifting of the mountain."
For more information, visit http://www.cnn.com.
|
|
|
|
|
