Atka

Atka volcanic center also includes the volcanoes Korovin and Kliuchef. Kliuchef showed a small amount of localised subsidence during 1997–1998, 1998–1999, and 2004 – 2005. Uplift in this region was then observed during 1999 – 2000, 2003 – 2004 and again in June 2006 continuing until the time of the last InSAR observations.
The source of deformation is located on the western flank of Kliuchef. The source of uplift is located at 5 – 7 km depth. The rate of volume increase is seen to fluctuate and is superimposed upon a trend of steady increase at 0.005 km³/yr. Uplift is attributed to an intrusion of magma into a storage zone 5–8 km beneath the summit area. The source of subsidence is located 3 – 4 km below the surface, and is likely to be due to depressurisation caused by cooling and fluid loss from the uppermost part of the magma storage zone and/or the overlying hydrothermal system.