Acoustic emission at the Stromboli volcano: scaling laws and seismic activity

We analyze acoustic emission data taken over several years at the Stromboli volcano on the Aolean Islands in Italy. The data consist of single acoustic events which are organized in clusters, called paroxysmal phases, each composed of up to millions of events. The distribution of amplitudes and temporal intervals were measured for both the elementary events and the clusters: common power laws were found, raising the question of a single underlying mechanism with a self-similar hierarchical structure ranging in time from seconds to months. Such scaling laws are interpreted based on the paradigm of self-organized criticality. Finally, we hint at a close temporal correlation between ultrasonic and volcanic activity.