WASHINGTON - A powerful earthquake that shook Alaska in 2002 affected geysers and hot springs at Yellowstone National Park nearly 2,000 miles away in Wyoming, scientists have reported.
The magnitude 7.9 Denali fault earthquake in November 2002 was known to have triggered smaller quakes across much of the U.S. West, but its effect on geysers was previously unknown, a team at the University of Utah said.
They monitored 22 of Yellowstone's 10,000 geysers, hot springs and steam vents. Eight "displayed notable changes in their eruption intervals" after the quake, they found.
"We did not expect to see these prolonged changes in the hydrothermal system," seismologist Robert Smith, who helped lead the study, said in a statement.
Writing in the June issue of the journal Geology, Smith and colleagues said they had recorded about 1,000 small and tiny quakes at Yellowstone after the Denali quake. They reported this phenomenon at the time.
But they have since found out that hot springs and geysers were affected.
"Several small hot springs, not known to have geysered before, suddenly surged into a heavy boil with eruptions as high as 1 meter (about 39 inches)," Smith and colleagues wrote in Geology.
"The temperature at one of these springs increased rapidly from about 42 to 93 degrees Celsius (about 108 to 199 degrees F)," they said.
It also became much less acidic than usual.
"In the same area, another hot spring that was usually clear showed muddy, turbid water," they wrote.
Perhaps some of the quake waves jarred loose minerals that had sealed some underground hot water conduits, Smith's team said.
A more alarming question remains, the team wrote.
"Could large earthquakes closer to Yellowstone trigger hydrothermal explosions?" they asked.
Thousands of years ago a steam and hot water explosion blasted out a hole that now is Mary's Bay on Yellowstone Lake.
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