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Inflation and deflation at the steep‐sided Llaima stratovolcano (Chile) detected by using InSAR
Author(s) -
Bathke H.,
Shirzaei M.,
Walter T. R.
Publication year - 2011
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2011gl047168
Subject(s) - deflation , stratovolcano , inflation (cosmology) , geology , interferometric synthetic aperture radar , geodesy , seismology , keynesian economics , economics , remote sensing , physics , volcano , synthetic aperture radar , monetary policy , lava , theoretical physics
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 × 10 6 m 3 during the subsidence period, followed by a volume increase of 6 – 20 × 10 6 m 3 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.