Smale, Lara;
(2020)
A Re-interpretation of Long-Term Deformation at Campi Flegrei caldera, Italy and Perceptions of the Causes of Caldera Unrest.
Doctoral thesis (Ph.D), UCL (University College London).
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Abstract
Campi Flegrei caldera has been in a state of unrest since 1950. Between 1950-1984 the centre of the caldera was raised c. 3.8 m by three rapid uplifts (c. 1 m yr-1). The third episode was followed by subsidence until 2004 (c. 0.9 m), when a slow uplift began that continues to Present (2019). The causes of the deformation are debated but common to all conventional models is that they cannot account for the change in the characteristics of deformation after 1984. This research focuses on identifying a potential cause for the change and on understanding the perceived role of the hydrothermal system in ground movements amongst scientists. By combining the results of a review of the caldera’s magmatic-hydrothermal system and behaviour with an analysis of the distribution of seismicity in relation to hydrothermal reservoirs, new model constraints were defined and deformation trends reinterpreted. Perceptions of unrest were investigated through a survey of 62 Italian scientists. The primary result is a new model for deformation that considers ground movements since 1950 to represent a single evolutionary sequence. It was recognised here that conditions in 1984 were favourable for an increase in bulk permeability in hydrothermal reservoirs below the deforming area as the crust was progressively fractured and faulted over successive uplifts. Based on this observation, post-1984 ground movements are attributed to a redistribution of pore pressure as reservoirs continue to adjust to the mechanical changes in the crust. Amongst surveyed scientists, there was a general perception that for the hydrothermal system to contribute to uplift it must be pressurised by either a magma intrusion or an injection of magmatic fluid, and that this is a pre-requisite in order for subsidence to occur as a result of pore pressure loss. The model can act as an end-member scenario for evaluating the evolution of uplift, whilst improved understanding of the perceived controls on deformation is a step towards improving communication of unrest.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Ph.D |
| Title: | A Re-interpretation of Long-Term Deformation at Campi Flegrei caldera, Italy and Perceptions of the Causes of Caldera Unrest |
| Event: | UCL (University College London) |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| Additional information: | Copyright © The Author 2020. Original content in this thesis is licensed under the terms of the Creative Commons Attribution 4.0 International (CC BY 4.0) Licence (https://creativecommons.org/licenses/by/4.0/). Any third-party copyright material present remains the property of its respective owner(s) and is licensed under its existing terms. Access may initially be restricted at the author’s request. |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Earth Sciences |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10097071 |
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