It is well known that infrasound sensing can detect pressure waves generated by explosive volcanic activity. Infrasound sensors deployed in an array allow to discriminate true signals from noise and to estimate the direction of arrival (DOA) while multiple arrays allow for source location and range.
Since 2007 the Experimental Geophysical Laboratory (LGS) of the University of Florence (http://lgs.geo.unifi.it) has been using infrasound array technique to detect and track in real-time explosive activity at Etna volcano, one of the most active volcanoes worldwide. Based on the amplitude and the rate of the infrasound detections, LGS developed an automatic infrasonic procedure to early warn lava fountain eruptions.
Since 2021, LGS has adopted Hermes sensors for Etna infrasound monitoring systems, relying on their reliability, robustness, and signal quality for continuous operation and real-time applications.
This infrasound-based early warning offers the opportunity to anticipate of more than one hour (~70 minutes) the most violent and critical phase of lava fountaining episodes. This violent explosive activity generates ash columns up to 15 km high in the troposphere, visible from tens of kilometers and potentially impacting air traffic. Incandescent scoria and ballistic blocks fall over a large area outside the craters, often visited by hikers and tourists.
The infrasound-based early warning provides therefore valuable information to promptly alert guides and tour operators, as well as to support the decision-making process of authorities and airlines.
Lunitek cooperates with GECO SRL (https://geco-company.com) and Experimental Geophysical Laboratory LGS of University of Florence (http://lgs.geo.unifi.it), specialists with decades of experience in the design of infrasonic arrays and the development of techniques and software for monitoring and studying active volcanoes worldwide.
Reference:
Ulivieri, G., Ripepe, M., & Marchetti, E. (2013). Infrasound reveals transition to oscillatory discharge regime during lava fountaining: Implication for early warning. Geophysical Research Letters, 40, 3008–3013. https://doi.org/10.1002/grl.50592
M. Ripepe, E. Marchetti, D. Delle Donne, R. Genco, L. Innocenti, G. Lacanna, and S. Valade. Infrasonic early warning system for explosive eruptions. Journal of Geophysical Research: Solid Earth, 123(11):9570–9585, 11 2018.
Hall, Shannon. (2018) “World’s first automated volcano forecast predicts Mount Etna’s eruptions.” Nature, vol. 5637731, 563(7732), pp. 456, DOI:10.1038/d41586-018-07420-y
Griff Jonathan, (2018) “New automated volcano warning system forecasts imminent eruptions”. American Geophysical Union. https://phys.org/news/2018-11-automated-volcano-imminent-eruptions.html
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