Dec. 3, 2004 — Scores of geologists are keeping their eyes riveted on Mount St. Helens, in Washington, for clues to help predict the violent whims of its kin that tower over metropolitan areas worldwide.

Mount St. Helens rumbled to life again in September, prompting geologists to elevate their alert level to the maximum third level early in October.

Though the volcano has since calmed, geologists have been monitoring its vital signs — earthquakes, escaping gases and ground surface swellings — in hopes of getting a better grasp of the workings of explosive "stratovolcanoes."

Small earthquakes — of magnitudes around 2 — have been steadily rolling in at a rate of one to two every minute, said geologist Jon Major, of the USGS Cascade Volcano Observatory, on Monday. The quakes are caused by magma moving up the throat of the volcano.

There have also been a few extra quakes topping 3 on the scale this week, which might mean something or nothing at all.

"The problem is, if you're only looking at seismicity, you're only looking at the elephant's trunk," said seismologist Steve Malone of the University of Washington and director of the Pacific Northwest Seismographic Network.

Malone was referring to the proverbial blind men who misidentified an elephant by feeling individual parts.

"(Together) we can all see a hazy outline of the elephant," said Malone.

To see the whole elephant, geologists studying many aspects of Mount St. Helens make frequent conference calls and brainstorm about what it all means, he said.

For instance, there is the continuing growth of "domes" in the volcano. These domes are caused by magma rising up from below and causing surface rocks to bulge upward. Measurements put the dome growth rate at about five to ten cubic meters every second. The rapid growth of domes, by itself, does not mean a large and violent eruption is imminent, however. It's just another part of the elephant.

"That's a pretty steady eruption rate," said Malone.

The rapid growth of domes, by itself, does not mean a large and violent eruption is imminent, however. It's just another part of the elephant.

Gases escaping the magma — like sulfur dioxide and carbon dioxide — have been measured and help gauge how much gas is in the magma. The more gas in the magma, the more explosive the potential eruption, said Major. Fortunately, the amount of gas that's being measured is still low, he said.

Gas-rich magmas are one of the signatures of stratovolcanoes and why they blow their tops like gigantic champagne corks. At the other end of the explosive volcano scale are "shield" volcanoes like those in the Hawaiian Islands, which have little gas and erupt without the towering clouds of ash that were seen pouring from Mount St. Helens in May of 1980.

Despite the low chance of a major eruption, geologists are working hard on Mount St. Helens in hopes that what they learn will be useful in predicting eruptions of other stratovolcanoes, some of which are located near major metropolitan areas around the world, said Malone.

"We don't have to look very far," said Malone.

Mt. Rainier, he points out, is a major stratovolcano overlooking the Seattle-Tacoma metropolitan area. "It's the next volcano in the chain," he said.