Interdisciplinary volcanology: Combining geochronology and geophysics at the Three Sisters volcanic complex

Annika Dechert

University of Oregon

As volcanologists, we look to the past to help us understand the future. We expect future eruption volumes, hazards, and timescales to loosely follow those of the past. This is a valuable assumption, but one that also needs to be considered. Specifically, does the magmatic system feeding the eruptions of the past match the modern-day magmatic system feeding the eruptions of the future? My research steps into this space, working to combine geochemistry, geochronology, and geophysics studies, connecting the past to the present.

The Three Sisters volcanic complex in central Oregon is a great place to tackle an interdisciplinary project. Through geochronology, we establish younger eruption ages of two South Sister rhyolites, suggest distinct magma bodies through time, and highlight how the older eruption sequence is valuable for future hazard mitigation. Through geophysics, we identify modern anomalies in the crust below the Three Sisters and explore how they could evolve through time. By combining these two distinct but complementary datasets, we can address similarities and differences between the past and modern magmatic systems at the Three Sisters to aid in future hazard mitigation.

Recent news coverage of Annika's work:

U of O scientists find that South Sister was more volcanically active over shorter time frame than previously thought

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