Doctorant/ Ph.D. Student
Modelling of volcano construction and degradation Laboratoire Géosciences Réunion - IPGP Université de la Réunion 15, Avenue René Cassin, BP 7151 97715 Saint Denis messagerie cedex 9 La Réunion phone: (33) 02 62 93 82 fax: (33) 02 62 93 82 66
Ph.D. student in Geology since 2007, La Réunion University
My PhD thesis deals with the analysis and modelling of the evolution of insular volcanoes, through a comparison between Aeolian Islands (Tyrrhenian sea, southern Italy) and La Reunion island (Indian Ocean, France). The PhD started in February 2008, in a partnership between:
- Università di Bologna, Dipartimento di Scienze della Terra e Geologico-ambientali
- Université de la Réunion, Laboratoire Géosciences Réunion.
Advisors: Claudia Romagnoli (Bologna) and Laurent Michon (La Reunion)
Summary of the research project: In the last few years, the study of the submarine flanks of main oceanic volcanoes (Hawai’i, Canary Islands…) proved that the evolution of these edifices is characterised by alternating phases of growth and destabilisation. The latter are linked to processes of gravitational instabilities, as shown by the presence of major debris avalanche deposits along the submarine flanks. The causes of the instability are diverse and mainly result from magmatic intrusions along rift-zones and/or the presence of low resistance layers within the volcanic edifice. Moreover, the geometries of the volcanoes and of their magmatic systems suggest that the evolution of insular volcanoes is controlled by other factors, like the basement or the structure of the surrounding crust. Both these parameters and the role of geodynamic context, remain poorly understood, as the extension of insular volcanoes is mainly submarine.
The objective of the project is to compare two volcanic systems, Aeolian Islands and La Reunion Island, located in different geodynamic contexts. While La Reunion Island is a 5 Myear-old volcanic system built in an intraplate context, on tectonically stable oceanic lithosphere, the volcanoes of the Aeolian arc, located in active subduction zone, have experimented historical activity.
On the basis of recent researches of marine geology in both areas, the phenomenon of lateral instabilities of volcanic flanks appears to have affected periodically these volcanic systems. As a consequence, the analysis and comparison between the two zones seems to be of great interest in order to reconstruct the evolution of the edifices, understanding the activation and development mechanisms of the instabilities, and to evaluate the associated hazards.
The realization of the project, based on a wide dataset, is divided into two complementary parts:
1- determination of main features of regional tectonic settings and geodynamic context for both areas.
2- analysis of the structure of submarine flanks of studied volcanoes, based on data collected during recent oceanographic campaigns (2003-2006 for Stromboli and Vulcano, 2003-2009 for La Reunion), with high-resolution bathymetric data, multi-channel seismic data and side-scan sonar images.
3- Numerical modelling of the relationship between regional tectonics, geodynamic context and internal deformation within oceanic volcanoes.
2006-2007 M.S.2 Earth Sciences, University of Clermont-Ferrand
2005-2006 M.S.1 Earth Sciences, University of Clermont-Ferrand
2004-2005 B.S.3 Earth Sciences, University of Clermont-Ferrand
2002-2004 Prepa Class “Biology Chemistry Physics and Earth Sciences”, Lille
January 2008: Participation to the oceanographic cruise ERODER-2, in the surroundings of La Reunion Island. Acquisition of bathymetrical and geophysical data on the submarine part of the island and the surrounding plate.
January-June 2007 :Research experience on the dynamics and impact of summit caldera collapse at Piton de la Fournaise volcano, La Reunion Island, France.
- Michon L., N. Villeneuve, Th. Catry, O. Merle (2009), How summit calderas collapse on basaltic volcanoes: new insights from the April 2007 caldera collapse of Piton de la Fournaise volcano. J. Volcanol. Geotherm. Res., special issue: Piton de La Fournaise, doi: 10.1016/j.jvolgeores.2008.11.003.