Muographic long-term monitoring of the Soufrière of Guadeloupe with a system of coupled muon detection systems

International audience; We present novel developments in muography methods to combine continuous measurementsperformed by 2 independant muon detectors around the dome of an active volcano, the Soufrièreof Guadeloupe. The aim is to reach the best possible performances in the continuous monitoringof its hydrothermal system spatio-temporal dynamics.Volcanic hydrothermal systems give rise to unpredictable hazards such as hydrothermal explo-sions, partial edifice collapse, mudflows and sudden emission of toxic gases. Characterizing the dy-namics of these systems and constraining the models by real-time data is thus critical for develop-ing efficient risk assessment.Within the DIAPHANE project, funded by the french National Research Agency (ANR), 6 muontelescopes have been deployed around the dome since 2015 and acquire muon data continuouslywith a large duty cycle. In this work we show the results obtained with a set of more than 1.5years of continuous measurements acquired with 2 muon detectors scanning different zones of thedome with large overlapping volumes. Characterizing the time changes in the outgoing muon fluxin different regions allows us to study the density changes caused by steam formation, condensa-tion, water infiltration and storage.The details of the analysis is presented : region definition through common geological structures,principal component analysis of the temporal series, determination of the changes in opacity im-plied by the muon-flux changes observed. This strategy allows us to spatially constrain the three-dimensional location of the coherent density changes and to improve the quantification of the as-sociated mass changes. The obtained results on the active zone of the Soufrière of Guadeloupe’sSouth crater are presented in details.