University of Firenze
INFRASOUND ARRAY MONITORING OF ICELANDIC VOLCANOES: NETWORK EFFICIENCY AND IMPROVEMENTS FOR EARLY WARNING.
Authors: G. Barfucci (Univ. of Firenze), K. Jonsdottir (Icelandic Met. Office), M. Ripepe (Univ. of Firenze), E. Marchetti (Univ. of Firenze),
Infrasound is reflecting the direct coupling of a volcanic source with the atmosphere and is the clear evidence that a volcanic eruption is ongoing. The ARISE project aims to establish an automatic notification system of volcanic eruptions in Iceland, where 4 small aperture, permanent, infrasound arrays have been deployed since 2010 by UNIFI and IMO and are now included into the Icelandic monitoring network.
We present here an analysis of the efficiency of the infrasonic network in terms of Early Warning System and we evaluate possible improvements of the actual geometry. The distance of the arrays from active volcanoes is spanning from a minimum of 19 km up to > 200 km, thus resulting into a complex propagation pattern with both tropospheric and stratospheric arrivals to be expected. This results into a time dependent efficiency of the network, caused by the seasonal variation of infrasound propagation and the consequent position and extension of the shadow zones.
In order to provide a robust and reliable early warning it is important to be able to detect direct waves that are less affected by seasonal and atmospheric variability than the stratospheric an thermospheric arrivals. Besides, an efficient Early Warning depends on the issue time of the alert.