Inflation and deflation at the steep-sided Llaima stratovolcano (Chile) detected by using InSAR
Abstract
Llaima volcano, Chile, is a typical basaltic-to-andesitic stratovolcano in the southcentral Andes. Llaima had at least four explosive eruptions in the decade 2000 - 2010, however little is known about the physical processes and magma storage at this volcano. In this study we present an InSAR deformation field at Llaima from 2003 - 2008, covering both the post-eruptive and syn-eruptive periods. The satellite InSAR data are significantly affected by environmental decorrelation due to steep topography, snow and vegetation; because of this, we applied a model-assisted phase unwrapping approach. The analysis of these data suggests two main deformation episodes: subsidence associated with the post-eruptive period, and uplift associated with the syn-eruptive period. Maximum summit subsidence and uplift are ∼10 cm and ∼8 cm, respectively. Through inverse modeling of both periods, a deflating and inflating magma body can be inferred, located at a depth of 4 - 12 km, subject to a volume decrease of 10 - 46 × 106 m3 during the subsidence period, followed by a volume increase of 6 - 20 × 106 m3 during the uplift period. Therefore, this study presents the first evidence of magma-driven deformation at Llaima volcano, and suggests that eruption periods are associated with the inflation and deflation of a deep magma body that can be monitored by using space geodesy.
- Publication:
-
Geophysical Research Letters
- Pub Date:
- May 2011
- DOI:
- 10.1029/2011GL047168
- Bibcode:
- 2011GeoRL..3810304B
- Keywords:
-
- Computational Geophysics: Modeling (1952;
- 4255;
- 4316);
- Geodesy and Gravity: Satellite geodesy: results (6929;
- 7215;
- 7230;
- 7240);
- Volcanology: Remote sensing of volcanoes (4337)