Seismic Evidence for a Low-Velocity Zone in the Upper Crust Beneath Mount Vesuvius

• Published in: Science (American Association for the Advancement of Science) 1996-10, Vol.274 (5287), p.592-594
• Main Authors: Zollo, A., Gasparini, P., Virieux, J., le Meur, H., de Natale, G., Biella, G., Boschi, E., Capuano, P., de Franco, R., dell'Aversna, P., de Matteis, R., Guerra, I., Iannaccone, G., Mirabile, L., Vilardo, G.
• Format: Article
• Language: English
• Subjects: Calderas; Carbonates; Crystalline rocks; Earth sciences; Earth, ocean, space; Earthquakes, seismology; Evidence; Exact sciences and technology; Igneous and metamorphic rocks petrology, volcanic processes, magmas; Individualized Instruction; Internal geophysics; Low speed; Maps (Geography); Profiles; Reflectors; Seismology; Tomography; Topographical surveying; Topography; Travel time; Two dimensional modeling; Volcanoes; Volcanology; Waveforms
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.274.5287.592

A two-dimensional active seismic experiment was performed on Mount Vesuvius: Explosive charges were set off at three sites, and the seismic signal along a dense line of 82 seismometers was recorded. A high-velocity basement, formed by Mesozoic carbonates, was identified 2 to 3 kilometers beneath the volcano. A slower (P-wave velocity V$_P$ ≃ 3.4 to 3.8 kilometers per second) and shallower high-velocity zone underlies the central part of the volcano. Large-amplitude late arrivals with a dominant horizontal wave motion and low-frequency content were identified as a P to S phase converted at a depth of about 10 kilometers at the top of a low-velocity zone (V$_P$ < 3 kilometers per second), which might represent a melting zone.