The shallow plumbing system of Stromboli Island as imaged from 1 Hz instantaneous GPS positions

Abstract

The Stromboli volcano (Aeolian Islands, Italy) erupted suddenly on 28 December 2002 after a 17-year period of typically persistent but moderate eruptive activity, followed two days later by a tsunamigenic landslide on its NW flank (Sciara del Fuoco) felt in the coastal areas of southern Italy. Three continuous GPS stations were quickly deployed near the volcano's rim sampling at 1 Hz, with instantaneous positions computed relative to a fourth station on its flank. We report on two deformation episodes. A vent migration on 16-17 February 2003 caused significant displacements at only one site and contributed to the decision not to issue a warning of an impending tsunamigenic landslide. The second episode on 5 April 2003, a paroxystic explosion from the summit crater, allowed us to model, for the first time with geodetic data, the shallow magma chambers that give rise to Strombolian explosive activity. Copyright 2004 by the American Geophysical Union.