An extensive area near the Three Sisters volcanic center, Oregon, has been actively uplifting since 1996. In this study we use Interferometric Synthetic Aperture Radar (InSAR) to assess the Three Sisters uplift in time and space from 1992 through 2010. We present the first InSAR line-of-sight time series of the deformation, refine the onset of volcanic intrusive activity, assess the changes in deformation through time, and determine whether inflation is still occurring. We model InSAR data to determine the source geometry that best describes the uplift and create an inflation time series of the deformation. Our results reveal an intrusion, located at ̃5-7 km depth with a cumulative volume of magma of ̃5-7 × 107 m3 as of fall 2010. The input of magma started gradually around the summer of 1996, increased significantly from 1998 to 2003, and then decreased in rate from 2004 through 2010. We present evidence that a swarm in 2004 was associated with the decrease in the source inflation rate.
Geochemistry, Geophysics, Geosystems
- Pub Date:
- December 2011
- Three Sisters;
- Geodesy and Gravity: Satellite geodesy: results (6929;
- Volcanology: Remote sensing of volcanoes (4337)