Lena CAUCHIE
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Probabilistic inversion of observed and simulated geophysical data at volcanoes
Personal Project in NEMOH
The overall goal of this project is a thorough investigation of the uncertainties related to the inversion of geophysical signals at active volcanoes. I will investigate how model simplifications of velocity structures and data errors affect the estimate of volcanic source properties (location, size and strength) obtained from inversion of geophysical data.
The project will start with the compilation of seismic velocity data over a range of scale lengths, for a representative test site (Etna and Campi Flegrei are the most suitable candidates). This includes collection of literature results, as well as processing of existing data sets. Then, Green's functions will be calculated for a set of sources and for any given source, for a suite of likely velocity models, so producing a library of Green's functions with associated error bounds due to uncertainties on the velocity structure.
Subsequently, a computer code for signal inversion will be developped accounting for the model uncertainties. It will first be applied to synthetic data generated assuming specific, simple source mechanism (i.e., crack-opening, explosions, etc.) aiming at an assessment of the errors induced by the combined effect of data and modeling uncertainties. Further, a study on the possible source mechanism associated with volcanic signals will be performed by inverting ground-truth data from the test site.
Scientific Background
I hold a Bachelor's degree in Physics and a M. Sc in Exploration and Applied Geophysics from the University of Pisa, Italy. In January 2010, I joined, as PhD student, the geophysics group in the School of Geological Science at the University College of Dublin, Ireland with the project title:"Analysis of the force system acting at seismo-volcanic sources". I first worked on the definition of shallow velocity structures in volcanic areas from inversion of surface waves dispersion characteristics.
Then I began to study the Long-Period activity on Mt. Etna through a statistical approach aiming at the understanding of its source mechanism. The behaviour of LP activity is compared with the empirical laws governing earthquakes recurrence (e.g., Gutenberg-Richter [GR] and Omori’s laws), in order to understand what relationships, if any, exist between these two apparently different earthquake classes. The analysis of LP activity has also been extended to other volcanic areas.
Contact:
Léna Cauchie
email:
