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Three Sisters Uplift

By Cascades Volcano Observatory
South, Middle, and North Sister volcanoes,Three Sisters OR. Seismic/GPS station, Three Sisters wilderness. View northwestward of South Sister volcano and unforested "Devils Chain" rhyolite lava domes. Interferogram spanning 2020-2021 and showing uplift west of South Sister GPS time series from station HUSB, 2001-2022 Deformation and geochemical anomalies near South Sister, Oregon Deformation near South Sister from GPS data, 2001-2017 Deformation and seismicity near South Sister during 2001-2022 South Sister volcano viewed northward from the east shore of Sparks Lake. Three Sisters volcanoes (left to right - South, Middle, and North) Three Sisters, Oregon

Detailed Description

In 2001, scientists discovered a broad area of uplift west of South Sister that had been rising a few cm (inches) per year since the 1990s.  Uplift rates have varied, with a new pulse starting in 2020–2021. Geochemistry data indicate that magmatic activity in the region predates the past few decades.

Sources/Usage

Public Domain.