Damage modeling at Piton de la Fournaise: linking seismicity and deformation patterns leading to eruptions

Seismicity rates and surface deformation records have just started to be used together in large-scale damage models of volcanic edifices. In these models, daily seismicity (VT events) can be interpreted as an indicator of the progress of damage, which plays a critical role in determining the mechanical behavior of the volcano. Seismicity and deformation can therefore be linked through the time-dependent evolution of the edifice elastic parameters. At various basaltic volcanoes, the analysis of seismic and GPS time-series of inter and pre-eruptive phases reveals a change in the volcano mechanical behavior a few weeks to months prior to eruptions, leading to an acceleration in seismic and deformation rates before the eruption. Piton de la Fournaise volcano (Reunion Island) is one of the most active hotspot volcanoes, with very frequent eruptions over the last three decades, and it is also equipped with one of the best monitoring network. Taking advantage of this exceptional record, we performed a systematic study of inter-eruptive time-series at Piton de la Fournaise since 2005 using damage models in order to identify pre-eruptive patterns, understand the changes in the volcano mechanical behavior, determine whether the repetitive characteristics of the signal could be interpreted as precursors, and characterize the long-term evolution of the reservoir dynamics.