SHALLOW-WATER VOLCANIC EDIFICES IN HIGH-RESOLUTION SEISMIC-REFLECTIONPROFILES - EXAMPLES FROM THE GULF OF NAPLES (ITALY)

The Gulf of Naples (southern Italy) is well known for active subaerial volcanism (Somma-Vesuvius and Phlegrean Fields). Several shallow subm arine volcanic edifices are known to exist around the Phlegrean area, but these have never been studied in detail. These volcanoes, located on the shelf, at a maximum depth of 150 m, are characterized by two di fferent seismic facies in high-resolution seismic reflection profiles: 1) chaotic reflections, with variable amplitude and frequency; 2) in- phase reflections, with low frequency and high amplitude or high frequ ency and low amplitude. Seismic facies (1) is interpreted as an image of massive volcanic deposits, such as lava flows, domes, pyroclastic f lows or lahars; while seismic facies (2) is interpreted as reflecting layered pyroclastic deposits, such as surge and fall deposits. This se ismic interpretation is confirmed by other geophysical and geological data available for the studied area.