An InSAR‐based survey of volcanic deformation in the southern Andes

Abstract

We use Interferometric Synthetic Aperture Radar (InSAR) to search for surface deformation in the southern Andes (40°S–46°S and 49°S–53°S) associated with magmatic processes. Although the available data are not optimal, we can constrain the amount of volcanic deformation at about 27 Holocene volcanoes between the years 1993–1999. We detect inflation of Cerro Hudson volcano following its 1991 eruption, and use spherical and non‐spherical models to constrain the source of deformation to be between 4 and 8 km below sea level. We measure the rate of deformation to be about 5 cm/year in the radar line‐of‐sight, and infer that the maximum deformation could exceed 10 cm/year in the center of the caldera. Within the errors of the measurements, the rate of deformation is constant from 1993–1998 (10–30 × 106 m3/year). At this rate, 100–200 years is required to accumulate the volume of material erupted in 1991.