Time-dependent deformation source model of Kilauea volcano obtained via InSAR time series and inversion modeling

Thursday, 18 December 2014
Guang Zhai and Manoochehr Shirzaei, Arizona State University, Tempe, AZ, United States
The Kilauea volcano, Hawaii Island, is one of the most active volcanoes worldwide. Its complex system including magma reservoirs and rift zones, provides a unique opportunity to investigate the dynamics of magma transport and supply. The relatively shallow magma reservoir beneath the caldera stores magma prior to eruption at the caldera or migration to the rift zones. Additionally, the temporally variable pressure in the magma reservoir causes changes in the stress field, driving dike propagation and occasional intrusions at the eastern rift zone. Thus constraining the time-dependent evolution of the magma reservoir plays an important role in understanding magma processes such as supply, storage, transport and eruption.

The recent development of space-based monitoring technology, InSAR (Interferometric synthetic aperture radar), allows the detection of subtle deformation of the surface at high spatial resolution and accuracy. In order to understand the dynamics of the magma chamber at Kilauea summit area and the associated stress field, we explored SAR data sets acquired in two overlapping tracks of Envisat SAR data during period 2003-2010. The combined InSAR time series includes 100 samples measuring summit deformation at unprecedented spatiotemporal resolutions. To investigate the source of the summit deformation field, we propose a novel time-dependent inverse modelling approach to constrain the dynamics of the reservoir volume change within the summit magma reservoir in three dimensions. In conjunction with seismic and gas data sets, the obtained time-dependent model could resolve the temporally variable relation between shallow and deep reservoirs, as well as their connection to the rift zone via stress changes. The data and model improve the understanding of the Kilauea plumbing system, physics of eruptions, mechanics of rift intrusions, and enhance eruption forecast models.