Laëtitia Pantobe has been awarded the 2026 Thesis Prize by the French National Committee for Geodesy and Geophysics (CNFGG).

Laëtitia Pantobe’s PhD thesis, defended on December 19, 2024, and supervised by Jean-Christophe Komorowski, Arnaud Burtin and Kristel Chanard, focuses on the characterization of microseismicity within the hydrothermal system of La Soufrière de Guadeloupe volcano. It led to the development of an automated processing workflow for the detection, magnitude estimation and location of microseismic events, now routinely used for operational monitoring of the volcano by the Observatoire Volcanologique et Sismologique de Guadeloupe (OVSG). The resulting catalog reveals that microseismicity is organized into swarms of repeating earthquakes located within a conduit less than one kilometer below the volcano’s summit.

Statistical analysis of this catalog highlights the existence of seasonal periodicities in microseismic activity. By combining seismic, geodetic and hydrological observations, this work identifies common modes of variability, demonstrating that microseismicity is modulated by external forcings, particularly hydrological ones. The modeling developed in this thesis shows that this modulation is primarily explained by a poroelastic response of the medium to fluid pressure variations within the shallow aquifer, in the same way that a sponge swells when exposed to water.

These results provide new insights into the dynamics of the hydrothermal system and open perspectives for improving the detection of subtle variations in internal activity, as well as the monitoring of phreatic eruptions.

The approaches and models developed in this thesis are transferable to other volcanic systems and provide a framework for more systematic monitoring of microseismicity in response to all types of forcings, in order to better track the internal evolution of volcanoes and improve volcanic hazard assessment and risk management.