Volcano number:312090
Country:United States
Geodetic measurements?Yes
Deformation observation?Yes
Measurement method(s):InSAR
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
Location:-158.17, 56.88

Aerial photo of Vent Mountain within Aniakchak Caldera. Source M. Livingston, U.S. Geological Survey AVO website