Friday, February 23, 2007
N.M. Tech scientists travel to Alaska to study an elusive phenomenon
By John Fleck
Journal Staff Writer
Paul Krehbiel and Ron Thomas had just taken a break for dinner when Mount St. Augustine erupted Jan. 27, 2006.
When the Alaskan volcano had begun popping off two weeks earlier, the New Mexico Tech lightning scientists had flown to Alaska, on the chance that the eruptions were not done.
"They said 'There's a good chance it'll erupt again,' '' Thomas said.
Normally thunderstorm chasers, the pair were hunting the elusive "volcano lightning."
Known since the ancient Greeks, volcano lightning comes from the hot, angry cloud of dust and ash rising from an erupting volcano.
Volcano lightning, similar to thunderstorm lightning, is created in the hurly-burly of collisions within the turbulent cloud of dust and gas rising from the exploding mountain.
But thunderstorms are easier to find than erupting volcanoes, so, while stories of volcano lightning abound, scientific data is scarce.
The pair are part of New Mexico Tech team that had just finished testing a new set of portable lightning detectors, and they were looking for a volcano to try them out on.
"About the only thing that was known about lightning associated with volcanos was that it occurs," said Tech professor Bill Rison, another member of the team.
A bit of serendipity connected the team with Steve McNutt at the Alaska Volcano Observatory, and when St. Augustine began erupting, they decided to fly up and give it a shot.
The results of their trip, published today in the journal Science, mark the first time scientists have ever captured detailed data on the elusive phenomenon.
McNutt had seen evidence for volcano lightning before, when the lightning's powerful electromagnetic pulses interfered with the electronics of seismic instruments he had set out around Mount Spur, another Alaskan volcano.
"The electronics guys weren't too happy about that," he said in a telephone interview.
But to understand lightning in detail takes special instruments antennas connected to sensitive receivers to map the peaks and values of the electromagnetic pulses flung out by the lightning bolts.
That is what Thomas and his colleagues brought to Alaska after hearing that St. Augustine, a volcano on Cook Inlet 60 miles west of Homer, was doing its thing.
"Their equipment is state of the art," McNutt said.
Hours after Thomas and Krehbiel got their gear set up, St. Augustine began its performance.
First, there was a crackle of lightninglike bursts from the volcano's mouth.
Then, as the cloud of dust and ash rose into the stormy nighttime sky, there were 300 lightning strikes over an 11- minute period as the cloud drifted south from the mountain's summit.
The results show complex patterns within the cloud as dust, rock fragments and water in the cloud banged into one another, according to the scientists.
More analysis is being done on the St. Augustine data, and the lightning detectors have been shipped off to an even colder volcano: Mount Erebus in Antarctica.