SMM, A New Seafloor Monitoring Module for Real-Time Data Transmission: an Application to Shallow Hydrothermal Vents

The hydrothermal activity represents an evidence of high-energy submarine processes related to active or recent volcanism. Shallow hydrothermal vents represent a unique study opportunity due to the easy access to the vented fluids. The hydrothermal fluids released off the coast of Panarea Island (Aeolian arc, Italy) have been intensively investigated since mid 80s. The sudden unrest of submarine volcanic activity occurred on November 2002 with a submarine low-energy explosion, dramatically changed the geochemical features and the degassing rate of the submarine hydrothermal vents and pushed the scientists to develop new methods to monitor the venting activity. A better inside of the whole submarine hydrothermal system has been achieved by the development of new investigations methods and geochemical models. The new information closely linking the geothermal and the volcanic activity of the Island require that a continuous monitoring of the submarine hydrothermal activity is carried out. sea-floor observatory has been developed for multidisciplinary monitoring activity and to perform real-time data transmission from the sea bottom. Among the other sensors, an acoustic probe, installed for a long-term recording of the sound of the bubbling gases in a frequency range of 0.5-3 kHz, gave useful information of a tight link between the submarine volcanic activity of Panarea Island and the crater explosions of the nearby active volcanic island of Stromboli.