Furnas

Volcano number:382100
Region:Atlantic Ocean
Country:Portugal
Geodetic measurements?Yes
Deformation observation?Yes
Measurement method(s):GPS - campaign
Duration of observation:1993 to 2002, 2008 to 2013
Inferred cause of deformation:Magmatic, Surface deposits, Faulting/tectonics
Characteristics of deformation:

São Miguel island hosts three stratovolcanoes: Sete CidadesÁgua de Pau (also called Fogo), and Furnas.

GPS campaign data between 1993 and 2002 show that deformation is driven by WNW–ESE tectonic extension at a rate slower than 5 mm yr−1 (Trota et al., 2006). GPS time series between 2008 and 2013 also show evidence for tectonic extension (Okada et al., 2014).

During a period of volcanic unrest at  Água de Pau between 2011 and 2012, two further sources of deformation were identified: 1) Permanent edifice-scale inflation centered at NE summit of Fogo, and 2) minor-scale inflation-deflation reversals between Congro, a trachyte maar east of Água de Pau and Furnas volcanoes (Okada et al., 2014).

 

Reference:Trota, A., Houlié, N., Briole, P., Gaspar, J. L., Sigmundsson, F., & Feigl, K. L. (2006). Deformation studies at Furnas and Sete Cidades Volcanoes (São Miguel Island, Azores). Velocities and further investigations. Geophysical Journal International, 166(2), 952-956.
Reference:Okada, J., Sigmundsson, F., Ofeigsson, B., Ferreira, T., Gaspar, J., Lorenzo, M., ... & Rodriques, R. (2014). Volcanic Unrest of Fogo Volcano in 2011-2012, S. Miguel Island, Azores, Observed by Continuous and Campaign GPS Analysis. In EGU General Assembly Conference Abstracts (Vol. 16, p. 13370).
Reference:Smithsonian Institution Global Volcanism Program
http://www.volcano.si.edu/volcano.cfm?vn=382100
Location:-25.32, 37.77