|Duration of observation:||1992 - 2010|
|Inferred cause of deformation:||Hydrothermal, Magmatic|
|Characteristics of deformation:|
InSAR measurements show that the caldera floor of Aniakchak volcano has subsided. The rate of subsidence decreased from ~12 mm/yr during 1992 – 2000 to ~8 mm/yr during 2000 – 2005 and ~6 mm/yr during 2005 – 2010. The deformation is modelled by a point source at shallow depth (2 – 4 km). Evidence from melt inclusions show that this is equal to preeruptive magma storage depths at the volcano. Subsidence may therefore be due to crystallisation or fluid loss from a shallow magma body. Another possible cause is a decrease in pore fluid pressure due to cooling or fluid loss from the hydrothermal system.
|Reference:||Kwoun, Oh-Ig, Lu, Zhong, Neal, Christina, and Wicks, Charles Jr., 2006, Quiescent deformation of the Aniakchak Caldera, Alaska, mapped by InSAR: Geology, v. 34, n. 1, p. 5-8.|
|Reference:||Lu, Z., and Dzurisin, D., 2014, InSAR imaging of Aleutian volcanoes: Chichester, UK, Springer-Praxis, 390 p.|
|Reference:||U.S. Geological Survey Alaska Volcano Observatory (AVO) website|
Aerial photo of Vent Mountain within Aniakchak Caldera. Source M. Livingston, U.S. Geological Survey AVO website