Augustine Volcano Rumbling Again

Recent changes with the Augustine Volcano indicate that the activity the volcano is exhibiting now is less explosive than what occurred in January.

Scientists, however, are continuing to keep an eye on the Cook Inlet volcano. Activity at the volcano climbed to a new level last week.

Measurements and observations made on Wednesday, Thursday and Friday show the nature of the activity is less hazardous than the explosive activity the volcano exhibited in mid-January.

Increased levels of carbon dioxide measured in emissions and overflight observations indicate recent seismicity is tied to dome building rather than explosions.

"Now we're in a period of big dome growth," said Peter Cervelli, a U.S. Geological Survey geophysicist with the Alaska Volcano Observatory.

Overflight observations and emissions measurements have found that the dome walls have accumulated more rock and that carbon dioxide levels have risen, indicating that the volcano is producing new magma. But new magma does not necessarily mean more explosions.

"Sometimes it comes out violently and sometimes it oozes out like a tube of toothpaste," Cervelli said. "And that's what it's doing right now."

The kind of lava that flows from Augustine tends to be cooler and thicker than the lava that flows from Hawaiian volcanoes.

Whether or not the volcano explodes or oozes depends on whether the path of the lava, and the gases contained in it, is obstructed.

"The system seems to be open and flowing now," said Rick Wessels, a research geophysicist for USGS and AVO.

The current toothpaste-like flow of lava from Augustine Volcano is building up the walls of the dome, causing occasional collapses and resulting in some of the increased seismic activity that has been measured over the course of the last couple of weeks.

Most of the recent low-elevation ash clouds can also be attributed to the collapses. The low-elevation ash clouds are not likely to travel far beyond the island.

Although explosive eruptive activity has not been ruled out for the near future, the volcano is likely to continue its current dome building activity for a couple of months, Cervelli said.