New integrated geodetic monitoring system at Stromboli volcano (Italy)

Stromboli is a composite volcano, forming the northernmost island of the Aeolian Archipelago volcanic arc (Tyrrhenian Sea). On December 28th 2002, lava flows outpoured from the northern wall of the NE crater and descended into the Sciara del Fuoco (SdF), a deep depression marking the NW flank of the volcano edifice. On December 30th 2002, two landslides occurred on the northern part of the SdF; they moved a mass in the order of tens of millions of cubic meters both above and below sea level. The landslide produced a tsunami causing significant damage to the eastern coast of the island, reaching the other Aeolian Islands and the Sicilian and southern Italian coasts. This event led to the upgrading of the ground deformation monitoring system, already existing on the island; the new requirement was the real-time detection of the deformations related to potential slope failures of the SdF. To this end, a remotely controlled monitoring system, based both on GPS and geodetic techniques, was planned and set up in a few months. The new monitoring system allowed to continuously measure the ground deformations occurring on the SdF, by integrating both terrestrial and satellite geodetic techniques. Although this system was severely damaged during the 7-month long eruption, it allowed to monitor important eruptive phases. For the first time, an accurate data set on the actual mass movements of the SdF and the crater area was available. It provided data that significantly supported the Civil Protection Authorities in making decisions and constrains theories related to landslide movements and volcanic activity. After the end of the eruption, the system was overhauled in order to optimize the instruments and set up a monitoring system aimed at measuring deformations forecasting other flank collapses.