We present the first density model of Stromboli volcano (Aeolian
Islands, Italy) obtained by simultaneously inverting land-based (543)
and sea-surface (327) relative gravity data. Modern positioning
technology, a 1 x 1 m digital elevation model, and a 15 x 15 m
bathymetric model made it possible to obtain a detailed 3-D density
model through an iteratively reweighted smoothness-constrained
least-squares inversion that explained the land-based gravity data to
0.09 mGal and the sea-surface data to 5 mGal. Our inverse formulation
avoids introducing any assumptions about density magnitudes. At 125 m
depth from the land surface, the inferred mean density of the island is
2380 kg m(-3), with corresponding 2.5 and 97.5 percentiles of 2200 and
2530 kg m-3. This density range covers the rock densities of new and
previously published samples of Paleostromboli I, Vancori, Neostromboli
and San Bartolo lava flows. High-density anomalies in the central and
southern part of the island can be related to two main degassing faults
crossing the island (N41 and NM) that are interpreted as preferential
regions of dyke intrusions. In addition, two low-density anomalies are
found in the northeastern part and in the summit area of the island.
These anomalies seem to be geographically related with past paroxysmal
explosive phreato-magmatic events that have played important roles in
the evolution of Stromboli Island by forming the Scari caldera and the
Neostromboli crater, respectively. (C) 2014 Elsevier B.V. All rights
reserved.