Earthquake-volcano link jolts Alaska scientists
An Alaskan news channel's website posted this article Friday, and I am posting the whole article since it is so darned significant. I have posted previously of the likelihood of an earthquake similar to the Indonesian one occurring near Seattle, which has a fault line under increasing pressure.
Fairbanks, Alaska - There is mounting evidence that the earthquake that triggered a killer tsunami in the Indian Ocean on Christmas weekend also triggered a second earthquake in Alaska.
That second quake was minor, but the fact that it happened at all was a revelation to scientists, who believe it provides a window into understanding volcanoes.
The first earthquake took place in the Indian Ocean, some 6,000 miles from the University of Alaska Fairbanks. But UAF seismologists say that, an hour after that massive quake occurred, they could actually detect the entire state of Alaska undulating up and down, rising and falling an inch or more every 30 seconds for several minutes.
The power that represents over such a distance is astounding, even to researchers.
But the quake did something more, something that scientists have not seen at that incredible distance. It actually triggered a second earthquake beneath Mount Wrangell, a 14,000-foot volcano about 50 miles east of Glennallen. “Wrangell is a pretty large volcano, with a large hydrothermal system,” explains Dr. John Sanchez of UAF. The mountain vents steam almost constantly and sits atop unstable volcanic faults.
“The ground is very hot at Mount Wrangell here,” says Dr. Michael West, also a researcher at UAF. “Despite a snow-covered mountain, you have open steaming areas of ground.” Restless Mount Wrangell, locked in fire and ice, would seem a world away from the tropical paradise of the Indian Ocean, but is now known to be seismically connected to it. Last December, when a huge earthquake generated a killer tsunami in the Indian Ocean, scientists watched as the quake sent a huge pulse of energy that actually engulfed the entire planet within a few hours. The event generated a power equivalent to 20,000 Hiroshimas.
“On the evening of Christmas Day here, the day after Christmas in Sumatra, after the earthquake occurred, it took about an hour for the large-amplitude seismic waves to make it to Alaska,” says Dr. West. UAF scientists watched as that pulse of energy, traveling at 6,000 mph raced toward Alaska and actually lifted the entire state an inch or more into the air. “The ground in Alaska -- in Anchorage and everywhere else through the state -- moved a couple of inches up and down during this time period,” West says. The heaving of the earth beneath Alaska triggered a series of magnitude 2 earthquakes beneath Mount Wrangell, 6,000 miles away from Indonesia. “Here in the summit of the volcano and this is the general area around which the little earthquakes happened, during the passage of the waves from the Sumatra earthquake,” Dr. Sanchez says.
The phenomenon of one earthquake triggering another earthquake at a distance of 6,000 miles -- a quarter of the circumference of the Earth -- has never been seen before. Now that it has happened, scientists are hoping it will provide insight into volcanic activity in Alaska and elsewhere. Gaining clues as to when volcanoes may become active again could be an important tool in saving lives.