Explosive activity at Mt. Etna summit craters and source modeling by using high-precision continuous tilt

We investigated the relationships between modelled strain produced by explosive activity through a volcanic conduit, observed paroxystic episodes on Mt. Etna, and high-precision continuous tilt signals recorded during such events from the tilt monitoring network. The tilt changes detected during two different explosive episodes were compared with those calculated from analytical models of ground deformation in order to constrain source properties. The July 22, 1998 subplinian explosion from Voragine crater produced small tilt changes (order of 0.5-1.5 mu rad) recorded over the entire volcano edifice, implying a small storage at nearly 2.5 km below sea level. The 1998-2000 period was characterized by tens of spectacular lava fountains from the South-East crater. Very small tilt change (similar to 0.1 mu rad) was recorded by a single station on the high north-eastem flank of Mt. Etna and indicated the action of a limited and shallow conduit with 1.5-1.9 km depth. These results provide a contribution to better infer the shallow plumbing system beneath Mt. Etna. (c) 2006 Elsevier B.V All rights reserved.