Abstract
We analyse a set of events, recorded in March 1984 during a period
of intense seismicity of the last bradyseismic crisis, to determine
shallow velocity models and seismic source moment tensors in the
Campi Flegrei region. The velocity models of the crust are obtained
by surface wave tomography. Two inland negative anomalies of group
velocity resulting in our tomographic maps well agree with previous
independent measurements whereas a third anomaly, located in the
Pozzuoli Gulf and not evidenced by previous studies, is in correspondence
with the caldera position. The inversion of the dispersion curves
allows us to extend the already available velocity models within
the uppermost 2 km of the crust. The obtained models are employed
to study seismic source features by the moment tensor analysis. Preliminary
synthetic tests are performed in order to minimise artefacts in the
moment tensor solutions possibly due to numerical noise, to station
distribution or to the structural modelling approximation. Most of
the investigated earthquakes are deviatoric mechanisms and the increase
of the isotropic component is observed in connection with the change
of the seismicity rate in the investigated temporal window.
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