Changes in the shallow magmatic system under Kilauea summit due to 2018 caldera collapse inferred from timeseries InSAR and finite element modelling

Abstract:

Kilauea, Hawaii is one of the most active volcanoes in the world with continuous magma activity at summit and multiple vents along the rift zone. The May 2018 eruption on the volcano caused a caldera collapse resulting in a volume change of 0.8 km³ under the summit [Lundgren et al. 2019]. In this study, we use interferometric synthetic aperture radar (InSAR) data to study the ground deformation from 2013 to 2020 which spans pre-eruptive inflation (2013-May 2018), co/post-eruptive deflation (May 2018 – September 2018) and ongoing inflation (starting September 2018). More than 500 Cosmo-SkyMed images were processed using small baseline subset (SBAS) technique to derive timeseries of deformation.

Changing patterns of deformation during the three time periods indicate the presence of multiple sources under the summit in form of stacked sills as suggested in Baker et al. 2012. In this study, we invert the obtained ground deformation for possible magma sources using Bayesian techniques (Bagnardi et al. 2018) and use finite element models to study the stress changes imparted by the caldera collapse to the summit magma system. Results from the study are immensely useful in predicting the future magma pathways and recharge under the caldera. Further, we investigate the influence of M6.9 earthquake which occurred coterminous with eruption, over the rift zone intrusion and caldera collapse.