Before Mount Redoubt erupted 20 years ago, satellites circling the globe beamed grayish images of volcano-swirling dust clouds back to earth. Scientists inside the then-new Alaska Volcano Observatory in Anchorage squinted at the images, trying to make sense of them.
To a surprising degree they succeeded. With data from seismometers they'd erected on Redoubt, 100 miles southwest of Anchorage, the AVO staff was able to warn the public on Dec. 13, 1989, that the volcano might soon erupt.
Less than a day later it did.
Now that Redoubt is rumbling again, some of the three dozen scientists who staff the observatory in Anchorage and Fairbanks say they're far better informed today, and better equipped to track its progress.
For one thing, there are satellites now that can peer down at that same confusing blob of grey clouds and pick out those that actually contain sulphur dioxide -- the tell-tale but colorless gas that gets belched from volcanoes -- and colorize it on a flat-screen monitor.
The monitors can tell the ash plume's temperature. They can predict which way it will blow at different elevations. They can track it around the world on the Internet, which wasn't fully available back then.
"Tracking the cloud -- it just wasn't done," says David Schneider, an AVO geophysicist who moved to Alaska to study Redoubt around the time of its last eruption.
There were far fewer satellites aloft back then, and only one was specifically configured to detect ash, Schneider said. Half of each day it was on the opposite side of Earth.
"Technology has changed from the point where we only had these (faxed) paper pictures of data -- to where we now have gigabytes of data ... every 15 to 30 minutes," Schneider said.
The observatory's "Operations Room" -- a bedroom-sized alcove in the old cinder-block U.S. Geological Survey Building on the campus of Alaska Pacific University -- is buzzing with data bits.
On one wall 18 flat-screen monitors wiggle nervously with "real-time" seismographic signals, all beamed to the building from the 31 Alaska volcanoes wired to record tremors and earthquakes.
Recent research shows that Alaska has more than 130 volcanoes that have been active in the last two million years -- and more than 50 that have been active since 1760, about 10 more than scientists were aware of two decades ago. About two of them erupt each year.
Now Redoubt is at center stage, and every breath it takes is carefully monitored. Nine seismographic stations have been positioned around its flanks and the surrounding terrain. Data from three of them can be observed 24 hours a day by anyone with computer access to the Internet.
For the most part, what those Redoubt seismographs show right now are signs of volcanic tremor -- an almost musical instrument-like vibration caused by fluid (part molten rock, part water) moving through the volcanic column.
But sometimes, deep inside the volcano, huge expanses of solid rock fracture apart under pressure -- and the blue line on the seismograph turns red as it slashes up and down, recording a sharp earthquake. In the same instant a low siren goes off in the "Ops" room, and everyone turns to check out the latest action.
SERIOUS THREAT
The stakes are high for the multi-agency AVO staff, which includes state geologists based in Fairbanks and researchers with the University of Alaska Fairbanks Geophysical Institute. Eruptions threaten lives.
When Redoubt last blew, a KLM Royal Dutch Airlines jet carrying 231 passengers flew into its ash cloud about 200 miles north of the volcano and lost power in all four engines. Fortunately they kicked back on -- after the plane plummeted nearly three miles -- and the jet landed safely in Anchorage.
Of course volcanoes pose a threat on land as well.
During Redoubt's last eruption, which shot a column of ash nearly seven miles high, burning-hot boulders the size of automobiles rained down on the mountain, triggering flows of hot gas that melted glaciers and launched mud slides. A massive flood surged down the Drift River basin, and workers at an oil terminal on the shore of Cook Inlet had to be quickly evacuated.
So AVO scientist-in-chief Thomas Murray, a volcano-sized man himself at 6-foot-8, has a call list memorized in the event of an impending eruption. Call No. 1: the Federal Aviation Administration, to alert pilots already in the air. No. 2: the National Weather Service, to forecast the direction of the ash cloud, so other planes might be grounded if necessary. No. 3: the United States Air Force, to protect national security.
In the case of Redoubt, other calls would follow quickly -- to the U.S. Coast Guard, the governor's office, the Drift River Oil Terminal. Then the flood of inbound calls would begin.
That's why all AVO geologists and geophysicists -- even those who are leaders in their field -- are trained to staff the telephone and answer questions from the public, Murray said.
"When the Homer School District superintendent calls up, like he did during the (2006) eruption of Augustine, and says, 'Do we close the school today or not?' -- you can't just say, 'Well, I need to do a little more research on it,' " says Murray. "The guy's asking for a yes or no answer."
And what did they tell him?
Says Murray: "I think it was (AVO geophysicist) Dave Schneider who hung up and said, 'The school kids are going to hate me for that one.'"
PRESSURE IS ON
High-tech tools notwithstanding, some things don't change, says AVO geologist Tina Neal, who moved to Alaska from a volcanology job in Hawaii during Redoubt's last eruption.
When observatory scientists need a sample of gas wafting up from the latest active volcano, they still gather it the old-fashioned way: by boarding a small plane and flying over the vent, then sticking their hand holding a canister out the window.
The density of sulphur dioxide molecules in the container tell them how many tons of gas are escaping each day, Neal said.
"Roughly the more magma you have, the more gas you're going to have."
But just as ominous is having the gas numbers suddenly plummet -- and the ground begin to shake -- when the volcano somehow gets plugged up and pressure pushes against the inside walls. That could trigger an eruption too.
As the pressure beneath Redoubt continues to build, new ground-based GPS monitors placed on the outskirts of the volcano are ready to detect any deformation in the landscape, since the crust of the earth swells as the magma swells.
Even land 20 miles away can move a centimeter or two due to a bulging volcano, and the highly sensitive GPS instruments can detect it, Neal said.
"St. Augustine volcano, just before it erupted, I think we saw three centimeters of motion."
That could make all the difference.
Find George Bryson online at adn.com/contact/gbryson or call 257-4318.
By GEORGE BRYSON
gbryson@adn.com