Askja

Volcano number:373060
Region:Iceland and Arctic Ocean
Country:Iceland
Geodetic measurements?Yes
Deformation observation?Yes
Measurement method(s):InSAR, GPS - continuous, GPS - campaign, Levelling, Strainmeter, Tiltmeter, EDM
Duration of observation:Continuous
Inferred cause of deformation:Magmatic, Faulting/tectonics
Characteristics of deformation:

Wright et al. (2012): Askja caldera has been subsiding since at least 1983, initially at about 5 cm yr−1, and more recently at a rate of ~3 cm yr−1. Measurements from 1966 to 1971 showed two years of uplift that was preceded by subsidence. The subsidence can be modelled by a pressure decrease in a shallow magma chamber at 2–3 km depth.

Eruptions have occurred in Askja between 1921 and 1929 and in 1961. The most recent episode of major rifting occurred in 1874–1876 (Wright et al., 2012). Askja is well monitored with InSAR, GPS, seismics and levelling. 

Reference:Smithsonian Institution Global Volcanism Program
http://www.volcano.si.edu/volcano.cfm?vn=372060
Reference:Wright, T. J., F. Sigmundsson, C. Pagli, M. Belachew, I. J. Hamling, Bryndís Brandsdóttir, D. Keir, R. Pedersen, A. Ayele, C. Ebinger, P. Einarsson, E. Lewi and E. Calais (2012), Geophysical constraints on the dynamics of spreading centres from rifting episodes on land, Nature Geoscience, 5, 242-250 (2012) doi:10.1038/ngeo1428, 2012.
Location:-16.75, 65.03

View of Askja volcano. Source: Smithsonian Institution Global Volcanism Program

Sourced from FutureVolc (http://futurevolc.hi.is/volcanoes-and-monitoring): “Iceland: volcanoes and present long-term monitoring stations. The volcanic areas consist of volcanic systems, made of central volcanoes, calderas and fissure swarms. Western Eastern, and Northern volcanic zones marked (WVZ, EVZ, NVZ) are located on the divergent plate boundary between the North-American and Eurasian plates. Iceland’s most active volcanoes are Grímsvötn (G) and Bárðarbunga (B) under the Vatnajökull ice cap, Katla (K) under Mýrdalsjökull ice cap, and Hekla (H). Eyjafjallajökull vocano is labelled E”.