In September 2001, an extensive active-seismic investigation (Serapis
experiment) was carried out in the Gulfs of Naples and Pozzuoli,
with the aim of investigating and reconstructing the shallow crustal
structure of the Campi Flegrei caldera, and possibly identifying
its feeding system at depth. The present study provides a joint analysis
of the very shallow seismic reflection data and tomographic images
based on the Serapis dataset. This is achieved by reflection seismic
sections obtained by the 3D data gathering and through refined P-velocity
images of the shallowest layer of Pozzuoli Gulf (z<1,000 m). From
the refined Vp model, the overall picture of the velocity distribution
confirms the presence of a complex arc-shaped anomaly that borders
the bay offshore. The deeper part of the anomaly (beneath 700 m,
with Vp>3,500 m/s) correlates with units made up of agglomerate tuffs
and interbedded lava, which form the southern edge of the caldera,
which was probably formed following the two large ignimbritic eruptions
that marked the evolutionary history of the area under study. The
upper part of the anomaly that tends to split into two parallel arcs
is correlated with dikes, volcanic mounds and hydrothermal alteration
zones noted in previous shallow reflection seismic analyses. The
depth of the transition between the upper and lower parts of the
anomaly is characterized by an abrupt Vp increase on the one-dimensional
(1D) profiles extracted from the 3D tomographic model and by the
presence of a strong reflector located at about 0.6/0.7 s Two Way
Time (TWT) on Common Mid Point gathers. The move-out velocity analysis
and stack of the P-P and P-S reflections at the layer bottom allowed
to estimate relatively high Vp/Vs values (3.7+-0.9). This hypothesis
has been tested by a theoretical rock physical modeling of the Vp/Vs
ratio as a function of porosity suggesting that the shallow layer
is likely formed by incoherent, water saturated, volcanic and marine
sediments that filled Pozzuoli Bay during the post-caldera activity.
%0 Journal Article
%1 delloiacono_etal:2009
%A Dello Iacono, Dario
%A Zollo, Aldo
%A Vassallo, Maurizio
%A Vanorio, Tiziana
%A Judenherc, Sebastien
%D 2009
%J Bulletin of Volcanology
%K geophysics seismics
%N 3
%P 275--284
%R 10.1007/s00445-008-0222-1
%T Seismic images and rock properties of the very shallow structure
of Campi Flegrei caldera (southern Italy)
%U http://dx.doi.org/10.1007/s00445-008-0222-1
%V 71
%X In September 2001, an extensive active-seismic investigation (Serapis
experiment) was carried out in the Gulfs of Naples and Pozzuoli,
with the aim of investigating and reconstructing the shallow crustal
structure of the Campi Flegrei caldera, and possibly identifying
its feeding system at depth. The present study provides a joint analysis
of the very shallow seismic reflection data and tomographic images
based on the Serapis dataset. This is achieved by reflection seismic
sections obtained by the 3D data gathering and through refined P-velocity
images of the shallowest layer of Pozzuoli Gulf (z<1,000 m). From
the refined Vp model, the overall picture of the velocity distribution
confirms the presence of a complex arc-shaped anomaly that borders
the bay offshore. The deeper part of the anomaly (beneath 700 m,
with Vp>3,500 m/s) correlates with units made up of agglomerate tuffs
and interbedded lava, which form the southern edge of the caldera,
which was probably formed following the two large ignimbritic eruptions
that marked the evolutionary history of the area under study. The
upper part of the anomaly that tends to split into two parallel arcs
is correlated with dikes, volcanic mounds and hydrothermal alteration
zones noted in previous shallow reflection seismic analyses. The
depth of the transition between the upper and lower parts of the
anomaly is characterized by an abrupt Vp increase on the one-dimensional
(1D) profiles extracted from the 3D tomographic model and by the
presence of a strong reflector located at about 0.6/0.7 s Two Way
Time (TWT) on Common Mid Point gathers. The move-out velocity analysis
and stack of the P-P and P-S reflections at the layer bottom allowed
to estimate relatively high Vp/Vs values (3.7+-0.9). This hypothesis
has been tested by a theoretical rock physical modeling of the Vp/Vs
ratio as a function of porosity suggesting that the shallow layer
is likely formed by incoherent, water saturated, volcanic and marine
sediments that filled Pozzuoli Bay during the post-caldera activity.
@article{delloiacono_etal:2009,
abstract = {In September 2001, an extensive active-seismic investigation (Serapis
experiment) was carried out in the Gulfs of Naples and Pozzuoli,
with the aim of investigating and reconstructing the shallow crustal
structure of the Campi Flegrei caldera, and possibly identifying
its feeding system at depth. The present study provides a joint analysis
of the very shallow seismic reflection data and tomographic images
based on the Serapis dataset. This is achieved by reflection seismic
sections obtained by the 3D data gathering and through refined P-velocity
images of the shallowest layer of Pozzuoli Gulf (z<1,000 m). From
the refined Vp model, the overall picture of the velocity distribution
confirms the presence of a complex arc-shaped anomaly that borders
the bay offshore. The deeper part of the anomaly (beneath 700 m,
with Vp>3,500 m/s) correlates with units made up of agglomerate tuffs
and interbedded lava, which form the southern edge of the caldera,
which was probably formed following the two large ignimbritic eruptions
that marked the evolutionary history of the area under study. The
upper part of the anomaly that tends to split into two parallel arcs
is correlated with dikes, volcanic mounds and hydrothermal alteration
zones noted in previous shallow reflection seismic analyses. The
depth of the transition between the upper and lower parts of the
anomaly is characterized by an abrupt Vp increase on the one-dimensional
(1D) profiles extracted from the 3D tomographic model and by the
presence of a strong reflector located at about 0.6/0.7 s Two Way
Time (TWT) on Common Mid Point gathers. The move-out velocity analysis
and stack of the P-P and P-S reflections at the layer bottom allowed
to estimate relatively high Vp/Vs values (3.7+-0.9). This hypothesis
has been tested by a theoretical rock physical modeling of the Vp/Vs
ratio as a function of porosity suggesting that the shallow layer
is likely formed by incoherent, water saturated, volcanic and marine
sediments that filled Pozzuoli Bay during the post-caldera activity.},
added-at = {2012-09-01T13:08:21.000+0200},
author = {Dello Iacono, Dario and Zollo, Aldo and Vassallo, Maurizio and Vanorio, Tiziana and Judenherc, Sebastien},
biburl = {https://www.bibsonomy.org/bibtex/2c7772a9eaf6060e64b8d35126eb0b3d9/nilsma},
day = 1,
doi = {10.1007/s00445-008-0222-1},
interhash = {d02f8eb2033c7eb9f76094e58dc4d2b8},
intrahash = {c7772a9eaf6060e64b8d35126eb0b3d9},
journal = {Bulletin of Volcanology},
keywords = {geophysics seismics},
month = apr,
number = 3,
pages = {275--284},
timestamp = {2021-02-09T13:27:42.000+0100},
title = {Seismic images and rock properties of the very shallow structure
of Campi Flegrei caldera (southern Italy)},
url = {http://dx.doi.org/10.1007/s00445-008-0222-1},
volume = 71,
year = 2009
}