Spatiotemporal model of Kīlauea's summit magmatic system inferred from InSAR time series and geometry-free time-dependent source inversion

Abstract

Kīlauea volcano, Hawai‘i Island, has a complex magmatic system including summit reservoirs and rift zones. Kinematic models of the summit reservoir have so far been limited to first-order analytical solutions with predetermined geometry. To explore the complex geometry and kinematics of the summit reservoir, we apply a multitrack wavelet-based InSAR (interferometric synthetic aperture radar) algorithm and a novel geometry-free time-dependent modeling scheme. To map spatiotemporally distributed surface deformation signals over Kīlauea's summit, we process synthetic aperture radar data sets from two overlapping tracks of the Envisat satellite, including 100 images during the period 2003–2010. Following validation against Global Positioning System data, we invert the surface deformation time series to constrain the spatiotemporal evolution of the magmatic system without any prior knowledge of the source geometry. The optimum model is characterized by a spheroidal and a tube-like zone of volume change beneath the summit and the southwest rift zone at 2–3 km depth, respectively. To reduce the model dimension, we apply a principal component analysis scheme, which allows for the identification of independent reservoirs. The first three PCs, explaining 99% (63.8%, 28.5%, and 6.6%, respectively) of the model, include six independent reservoirs with a complex interaction suggested by temporal analysis. The data and model presented here, in agreement with earlier studies, improve the understanding of Kīlauea's plumbing system through enhancing the knowledge of temporally variable magma supply, storage, and transport beneath the summit, and verify the link between summit magmatic activity, seismicity, and rift intrusions.