Crustal seismic velocity responds to a magmatic intrusion and seasonal loading in Iceland's Northern Volcanic Zone.

• Main Authors: Donaldson, C, Winder, T, Caudron, C, White, RS
• Format: Article in Journal/Newspaper
• Language: English
• Published: American Association for the Advancement of Science (AAAS) 2019
• Subjects: 37 Earth Sciences; 3705 Geology; 3706 Geophysics; Holuhraun; Iceland
• Online Access: https://www.repository.cam.ac.uk/handle/1810/297868; https://doi.org/10.17863/CAM.44925

Seismic noise interferometry is an exciting technique for studying volcanoes, providing a continuous measurement of seismic velocity changes (dv/v), which are sensitive to magmatic processes that affect the surrounding crust. However, understanding the exact mechanisms causing changes in dv/v is often difficult. We present dv/v measurements over 10 years in central Iceland, measured using single-station cross-component correlation functions from 51 instruments across a range of frequency bands. We observe a linear correlation between changes in dv/v and volumetric strain at stations in regions of both compression and dilatation associated with the 2014 Bárðarbunga-Holuhraun dike intrusion. Furthermore, a clear seasonal cycle in dv/v is modeled as resulting from elastic and poroelastic responses to changing snow thickness, atmospheric pressure, and groundwater level. This study comprehensively explains variations in dv/v arising from diverse crustal stresses and highlights the importance of deformation modeling when interpreting dv/v, with implications for volcano and environmental monitoring worldwide. Seismometers were borrowed from the Natural Environment Research Council (NERC) SEIS-UK [loans 968 and 1022], with funding by research grants from the NERC and the European Community’s Seventh Framework Programme [grant 885 308377, Project FUTUREVOLC], and graduate studentships from the NERC (NE/L002507/1).