[1] We combine new observations of volcano deformation in Latin America with more than 100 previous deformation studies in other areas of the world to constrain the frequency, magnitude, and duration of subaerial volcano deformation events. We discuss implications for eruptive hazards from a given deformation event and the optimum repeat interval for proposed InSAR satellite missions. We use L band (23.6 cm wavelength) satellite-based interferometric synthetic aperture radar (InSAR) to make the first systematic search for deformation in all volcanic arcs of Latin America (including Mexico, Central America, the Caribbean, and the northern and southern Andes), spanning 2006-2008. We combine L and C band (5.6 cm wavelength) InSAR observations over the southern Andes volcanoes to extend the time series from 2002 to 2008 and assess the capabilities of the different radars: L band gives superior results in highly vegetated areas. Our observations reveal 11 areas of volcano deformation, some of them in areas that were thought to be dormant. There is a lack of observed deformation at several erupting volcanoes, probably due to temporal aliasing. The total number of deforming volcanoes in the central and southern Andes now totals 15 (from observations between 1992 and 2008), comparable to the Alaska/Aleutian arc. Globally, volcanoes deform across a variety of time scales (from seconds to centuries) often without eruption and with no apparent critical observation time scale, although observations made every minute are sometimes necessary to see precursors to eruption.

[1] 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 × 10 7 m 3 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.

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