High resolution imaging of small scale volcanic deformations : application to Lascar volcano, Chile
Abstract
Numerous studies have demonstrated the potentialities of satellite SAR (Synthetic Aperture Radar) interferometry for measuring ground deformations related with volcanic activity. Nevertheless, explosive andesitic volcanoes appeared to be less suited for interferometry studies due to specific geometry, environmental conditions, images availability. As a matter of fact, very few studies have been conducted on stratovolcanoes even though significant topographic changes are likely to occur at various scales (lava dome collapse, flank destabilization, etc.). Moreover, the rough field conditions such as observed on Andean volcanoes, do not allow to properly perform ground monitoring tasks and precise geodetic observations are often rare or inadequate to improve our knowledge of ground deformation processes. Lascar (5592 m) is one of the most active volcanoes of the northern Chilean Andes. Its recent activity is characterized by repetitive dome growth and subsidence accompanied by vigorous degassing and explosive eruptions of various magnitude. Interferometric analysis of Synthetic Aperture radar images acquired by ERS-1/2 and JERS over Lascar volcano did not revealed any large scale ground deformation associated to recent volcanic activity (1993-2000). With the aim to attempt a better quantification of small scale deformations, we performed a high resolution imaging over the crater area based on SAR interferometry and precise DEM derived from aerial photogrammetry constrained by differential GPS data. Our results are discussed in relation with the proposed model of activity for Lascar volcano. Also, these results enhance the potentialities to combine satellite and ground observations to better monitor short wavelength surface changes on andesitic volcanoes as those related with degassing or lava dome extrusion/collapse processes.
- Publication:
-
EGS - AGU - EUG Joint Assembly
- Pub Date:
- April 2003
- Bibcode:
- 2003EAEJA....13246R