Scientists update eruption history of Oregon's South Sister volcano

A hiker's pack usually gets lighter over time as they plow through trail mix and water, but Annika Dechert likes to joke that hers gets heavier. As an Earth sciences graduate student at the University of Oregon, she's picking up clues to the eruption history of South Sister volcano in the Oregon Cascades, helping scientists better understand its possible future risk. Those clues: 10-pound chunks of crystal-studded rocks, ejected during past eruptions spanning 39,000 to 2,000 years ago and hauled off the volcano by Dechert and a team of volcanologists.