Magmatic activity beneath the quiescent Three Sisters volcanic center, central Oregon Cascade Range, USA
Article first published online: 11 APR 2002
Copyright 2002 by the American Geophysical Union.
Geophysical Research Letters
Volume 29, Issue 7, pages 26-1–26-4, April 2002
How to Cite
Magmatic activity beneath the quiescent Three Sisters volcanic center, central Oregon Cascade Range, USA, Geophys. Res. Lett., 29(7), doi:10.1029/2001GL014205, 2002., , , , , and ,
- Issue published online: 11 APR 2002
- Article first published online: 11 APR 2002
- Manuscript Accepted: 11 JAN 2002
- Manuscript Received: 10 OCT 2001
 Images from satellite interferometric synthetic aperture radar (InSAR) reveal uplift of a broad ∼10 km by 20 km area in the Three Sisters volcanic center of the central Oregon Cascade Range, ∼130 km south of Mt. St. Helens. The last eruption in the volcanic center occurred ∼1500 years ago. Multiple satellite images from 1992 through 2000 indicate that most if not all of ∼100 mm of observed uplift occurred between September 1998 and October 2000. Geochemical (water chemistry) anomalies, first noted during 1990, coincide with the area of uplift and suggest the existence of a crustal magma reservoir prior to the uplift. We interpret the uplift as inflation caused by an ongoing episode of magma intrusion at a depth of ∼6.5 km.