Kiska

Volcano number:311020
Region:Alaska
Country:United States
Geodetic measurements?Yes
Deformation observation?Yes
Measurement method(s):InSAR
Duration of observation:1995 - 2009
Inferred cause of deformation:Hydrothermal
Characteristics of deformation:

Between 1999 – 2000, Kiska volcano subsided by up to 7 cm (volume decrease 0.00003 km³). Interferograms spanning 2000 – 2001 suggest that subsidence continued but at a lower rate (maxmimum displacements ~2 cm). During 2004 – 2005, no deformation occured, but in 2005 – 2006 the summit area of the volcano uplifted by 3 – 4 cm (volume increase 0.00001 km³). The volcano then again subsided between 2006 – 2008 by ~3 cm (volume decrease 0.000005 km³). Overall these observations suggest that during times of quiescence, Kiska alternately uplifts and subsided, with a subsidence prevailing in the long term.

Deformation at Kiska volcano is modelled as a point source. This source is located 0.7 – 1 km below the summit, which suggests that deformation occurs due to pressure changes in the shallow hydrothermal system within the edifice. Uplift occurs when there is a heat flux into the self-sealed reservoir, increasing pore fluid pressure. Subsidence occurs when there is failure of the reservoir.

Reference:Lu Z., Masterlark, T., Power, J., Dzurisin, D., & Wicks, C. (2002c), Subsidence at Kiska volcano, western Aleutians, detected by satellite radar interferometry. Geophysical Research Letters, 29, doi:10.1029/2002GL014948.
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
http://www.avo.alaska.edu/volcanoes/volcinfo.php?volcname=Kiska
Location:177.602, 52.103

Aerial photo of Kiska. Source R. Clifford, U.S. Geological Survey AVO website