Depuis 1989, membre du Task Group Environmental Effects of Volcanism IAVCEI (International Association of Volcanology and Chemistry of the Earth's Interior)-IGBP (International Geosphere Biosphere Program). cfr. Bulletin of Volcanology (1990),V.52:494-506

Depuis 1992: membre du Steering comitee de l'IWGCL (International Working Group on the Chemistry of Crater Lakes) qui dépend de l'IAVCEI.

Reviewer pour diverses publications internationales: American Journal of Science, NATURE, Geochemical Journal, J. Geophysical Research, Geology, UNESCO, Mineralogical Society of America.

Reviewer de programmes de recherches: - pour la DG XII, Directorate General for Science, Research and Development, Commission of the European Communities: "Climatology and Natural Hazards".- pour le National Environment Research Council, United Kingdom.