Retrieving 65 years of volcano summit deformation from multitemporal structure from motion: The case of Piton de la Fournaise (La Réunion Island)

Allan Derrien (1) , Nicolas Villeneuve (1) , Aline Peltier (1) , François Beauducel (1)

1 IPGP - Institut de Physique du Globe de Paris

The structure from motion photogrammetry technique enables use of historical airborne photography to achieve high-resolution 3-D terrain models. We apply this method on Piton de la Fournaise volcano (La Réunion), which allows a unique opportunity to retrieve high-resolution (1.5-0.11 m) digital elevation models and precise deformation maps of the volcano since 1950. Our results provide evidence that the summit volume increased throughout the study period, at a stable rate of 2.2 Mm³/yr between 1950 and 2015, with an acceleration up to 8.0 Mm³/yr prior to the major 2007 eruption that was accompanied by summit caldera collapse. At the same time, summit deformation was asymmetric, with 9.2 ± 2.5 m of eastward seaward displacement and 1.3 ± 2.5 m to the west during 1950-2015. Our results reveal a temporal evolution in the volcano magma influx rate and deformation. Tracking these fluxes and the long-lived preferential eastern motion is crucial to mitigate risks associated to flank destabilization.

Keywords: structure from motion; Piton de la Fournaise; magma influx rate; cross correlation; strain

Domains: Sciences of the Universe [physics]

Allan Derrien, Nicolas Villeneuve, Aline Peltier, François Beauducel. Retrieving 65 years of volcano summit deformation from multitemporal structure from motion: The case of Piton de la Fournaise (La Réunion Island). Geophysical Research Letters, 2015, 42, pp.6959-6966. ⟨10.1002/2015GL064820⟩. ⟨insu-03579672⟩