Black smoke and ash drift skyward as Mount St. Helens erupts, sending a mushroom-shaped cloud more than 16,000 feet into the atmosphere on Sunday morning, March 30, 1980. Mount Rainier, Washington's highest mountain, is in the background. (AP Photo)
COUGAR, WA (KPTV) -
First things first: There are no signs of an impending volcanic eruption on Mount St. Helens.
But scientists with the Cascades Volcano Observatory said the volcano remains active and is showing "long-term uplift" and earthquake activity.
Ever since the sudden reawakening of Mount St. Helens in 2004, scientists have been monitoring the subtle inflation of the ground surface and the minor quake activity.
From 2004 to 2008, more than 35,000 Olympic swimming pools worth of lava erupted onto the crater floor. That period of eruption, however, didn't produce much in the way of explosive events.
Now, USGS experts said they're seeing volcanic behavior reminiscent to what happened after the 1980 to 1986 phase of eruptions.
The scientists said their analysis shows the magma reservoir beneath Mount St. Helens has been slowly re-pressurizing since 2008 and that it's likely caused by the arrival of a small amount of magma beneath the surface.
The re-pressurization of a volcano's magma reservoir can continue many years without an eruption, and the USGS says the latest analysis "does not indicate that the volcano is likely to erupt anytime soon."
This summer, scientists and volcano experts will perform surveys measuring the types and amounts of volcanic gases being released, plus the strength of the gravity field at the volcano. They'll also continue monitoring ground deformation and seismicity at the volcano.