High-resolution onshore seismic imaging of complex volcanic structures: An example from Vulcano Island, Italy

Abstract

Detailed seismic images of subsurface structures of volcanic calderas are fundamental to improve the structural and volcanological knowledge of these high-risk volcanoes. However, high-quality seismic data are difficult to obtain in volcanic areas, especially on shore. We report the results of a high-resolution seismic profiling of the western sector of La Fossa Caldera (Vulcano Island, Italy). Using a high-resolution vibrating source and both alternative acquisition and processing techniques, we were able to overcome most of the inconvenience caused by volcanic lithotypes. This study provides the subsurface distribution of volcanic deposits as well as the recognition of some significant intracaldera structures. We located a parasitic vent or hyaloclastite mound buried under La Fossa Caldera, which is dissipating CO 2 in an area where earthquakes have been recorded at about 1 km depth. Furthermore, the deformation pattern found at the southernmost part of the profile is consistent with a caldera collapse after a dome intrusion. The results suggest that the use of high-resolution vibrating sources combined with alternative seismic acquisition techniques and nonconventional processing could help to recover detailed information on the shallow structures of volcanic areas. Copyright 2009 by the American Geophysical Union.