Please use this identifier to cite or link to this item:
http://hdl.handle.net/2122/6989
Authors: | Trasatti, E.* Bonafede, M.* Ferrari, C.* Giunchi, C.* Berrino, G.* |
Title: | On deformation sources in volcanic areas: Modeling the Campi Flegrei (Italy) 1982–84 unrest | Journal: | Earth and Planetary Science Letters | Series/Report no.: | 3-4/306(2011) | Publisher: | Elsevier | Issue Date: | 2011 | DOI: | 10.1016/j.epsl.2011.03.033 | Keywords: | volcanic source unrest finite element inverse theory |
Subject Classification: | 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring | Abstract: | Deformation sources in volcanic areas are generally modeled in terms of pressurized tri-axial ellipsoids or pressurized cracks with simple geometrical shapes, embedded in a homogeneous half-space. However, the assumption of a particular source mechanism and the neglect of medium heterogeneities bias significantly the estimate of source parameters. A more general approach describes the deformation source in terms of a suitable moment tensor. Ratios between moment tensor eigenvalues are shown to provide a strong diagnostic tool for the physical interpretation of the deformation source and medium heterogeneities may be accounted for through 3D finite element computations. Leveling and EDM data, collected during the 1982–84 unrest episode at Campi Flegrei (Italy), are employed to retrieve the complete moment tensor according to a Bayesian inversion procedure, considering the heterogeneous elastic structure of the volcanic area. Best fitting moment tensors are found to be incompatible with any pressurized ellipsoid or crack. Taking into account the deflation of a deeper magma reservoir, which accompanies the inflation of a shallower source, data fit improves considerably but the retrieved moment tensor of the shallow source is found to be incompatible with pressurized ellipsoids, still. Looking for alternative physical models of the dislocation source, we find that the best fit moment tensor can be best interpreted in terms of a mixed mode (shear and tensile) dislocation at 5.5 km depth, striking EW and dipping by ~25°–30° to the North. Gravity changes are found to be compatible with the intrusion of ~60–70·10^6 m^3 of volatile rich magma with density ~2400 kg/m^3. |
Appears in Collections: | Article published / in press |
Files in This Item:
File | Description | Size | Format | Existing users please Login |
---|---|---|---|---|
2011_EPSL_cf.pdf | Main article | 1.62 MB | Adobe PDF |
WEB OF SCIENCETM
Citations
20
31
checked on Feb 10, 2021
Page view(s) 50
700
checked on Apr 17, 2024
Download(s)
21
checked on Apr 17, 2024