Time evolution of medium and long-period ground tilting at Campi Flegrei caldera
2020
Abstract. We analyse tiltmeter time series recorded from April 2015 to March 2019 at three borehole
instruments installed at Campi Flegrei caldera (Italy). We evaluate the crustal response in terms
of ground tilting to external excitations of medium/long-period tidal constituents by applying
a polarization analysis. The azimuths of the tilt vectors show well-defined polarization
directions and the ground tilting planes oscillate with the periodicity of the corresponding tidal
constituents. For two of the three tiltmeters, the average ground oscillation pattern related to
the monthly Mm and fortnightly Mf constituents show seasonal variations, which can be ascribed to
rainfall-induced tilting. In addition, for the same two instruments, a clear seasonal amplitude
modulation of the diurnal S1 constituent appears in the time series, revealing the occurrence of
site thermoelastic effects. The results indicate that the tidal tilting is mainly controlled by
the local stress field distribution and rheology; in addition, seasonal exogenous factors like
rainfalls play a role in modulating the ground deformation.
Keywords:
- Correction
- Source
- Cite
- Save
- Machine Reading By IdeaReader
18
References
11
Citations
NaN
KQI