Tracking eruptive phenomena by infrasound: May 13, 2008 eruption at Mt. Etna

Active volcanoes produce inaudible infrasound due to the coupling between surface magmatic processes and the atmosphere. Monitoring techniques based on infrasound measurements have been proved capable of producing information during volcanic crises. We report observations collected from an infrasound network on Mt. Etna which enabled us to detect and locate a new summit eruption on May 13, 2008 when poor weather inhibited direct observations. Three families of signals were identified that allowed the evolution of the eruption to be accurately tracked in real-time. Each family is representative of a different active vent, producing different waveforms due to their varying geometry. Several competitive models have been developed to explain the source mechanisms of the infrasonic events, but according to our studies we demonstrate that two source models coexist at Mt. Etna during the investigated period. Such a monitoring system represents a breakthrough in the ability to monitor and understand volcanic phenomena.