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Complex wave propagation in the Campi Flegrei Caldera, Italy,from Source and receiver-array analysis of sea-shot recordings
- Publication date
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- OGS
Abstract
We investigate wave propagation in the complex shallow crust of Campi Flegrei
Volcanic Complex, Italy, using array recordings of air-guns. We apply source- and
receiver-array analysis to define the independent variation of horizontal slowness at
both the source and receiver regions. This method allows the identification of
asymmetric ray-paths associated with near-source and near-observer velocity
heterogeneities. P-wave wave-vectors at both the source and receiver arrays depict
discrepancies as large as 50° with respect to the values expected for the 3D velocity
structure of the Gulf. At the source region, these discrepancies may be associated with
either un-modelled complexities in the geometry of the buried caldera rim, or with
velocity variations beneath the source-array. At the receiver array, the inferred
anomalies may be attributed to velocity variations marking the Solfatara crater rim, or
to a near-receiver, low-velocity body whose position would coincide with negative
gravimetric anomalies and a low Vp/Vs ratio region inferred by independent
geophysical and seismological studies