Sisters Uplift

The cluster of glaciated stratovolcanoes called the Three Sisters extends for 20 km (12 mi) along the crest of the Cascade Range in Oregon, 35 km (20 mi) west of the city of Bend and 100 km (60 mi) east of Eugene.

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.