Quakes, Instruments Signal New Eruption Soon at Mt. St. Helens, U.S. Geologist Says

Earthquakes rumbled with increasing frequency beneath Mt. St. Helens on Tuesday, and scientists predicted that the volcano was about to erupt again.

“Earthquakes are continuing at a slightly higher rate than 24 hours ago,” U.S. Geological Survey spokesman Steven Brantley said.

The federal agency issued an advisory Monday night warning of “renewed eruptive activity within the next two weeks, possibly within the next few days” at the southwest Washington peak, which blew its top in a massive eruption five years ago that left 57 persons dead or missing.

Since the devastating 1980 blast, scientists have been able to predict 15 of the volcano’s 17 subsequent eruptive episodes, officials said. The other two events were minor belches.

Instruments placed on and around the 80-story dome of lava on the floor of the volcano’s crater were measuring displacement across a crack atop the dome, Brantley said.

“All of these things indicate activity at the mountain is continuing to increase slowly,” he said.

Taking advantage of clearing weather, scientists headed for the crater Tuesday to measure the rate of swelling on the lava dome.

“We’re anxious to get inside,” Brantley said. “There is a risk to geologists working in the crater that we face during the buildup toward an eruption. It is a risk we gauge very carefully and that, in the end, must be accepted by the people who work there.”

The rate of ground deformation on the floor of the mile-wide crater also has increased.

“One reason we think it may be explosive is that the mountain has been extremely quiet for eight months,” Brantley said. “There’s also been a prolonged lull in the normal vigorous emissions of gas and ash from atop the dome.”