St. Helens Growing Slowly, Steadily

One year after Mt. St. Helens awoke from its slumber, the volcano that is slowly rebuilding itself is still generating excitement and wonder among scientists.

At a briefing Friday to celebrate the one-year anniversary of an intense swarm of earthquakes that signaled the volcano’s reawakening after 18 years of relative quiet, scientists with the U.S. Geological Survey at the Cascades Volcano Laboratory in Vancouver, Wash., shared what they’ve learned so far.

The volcano has been spitting out magma at a slow, steady rate ever since the molten rock first flowed to the surface last October, and there’s no sign this buildup will stop or become explosive any time soon.

Scientists feel confident about that in part because of something they’ve learned about the magma now oozing from the volcano. It contains much smaller amounts of explosive gas than did the magma in the 1980 Mt. St. Helens eruption, which killed 57 people and sent a river of hot mud and ash down the Toutle River Valley.

The current magma flow’s continuous upward movement may also be easing pressure that could otherwise contribute to a new, more explosive eruption.

Although things could change at any time, scientists aren’t expecting a big event soon.

Just in case something does change, however, geologist Dan Dzurisin, 53, who has studied the volcano after each of the developments since 1980, isn’t making retirement plans.

He said the current eruption could last months, years or even decades.

The new lava dome is growing about six times faster than it did during the six years of dome-building between 1980 and 1986.

“We’re confident the volcano would give us a warning of a major change,” Dzurisin said. “Before potentially explosive magma reaches the surface, we expect to have warning.... That’s our answer and we’re sticking to it.”