G31C-05
Advanced DInSAR analysis at Campi Flegrei and Vesuvius, Italy
Wednesday, 16 December 2015: 09:00
2002 (Moscone West)
Kristy French Tiampo1,2, Antonio G. Camacho3, Jose Fernandez3, Pablo J Gonzalez4 and Sergey V Samsonov5, (1)University of Western Ontario, Department of Earth Sciences, London, ON, Canada, (2)Cooperative Institute for Research in Environmental Sciences, Department of Geological Sciences, Boulder, CO, United States, (3)Institute of Geosciences (CSIC-UCM), Plaza de Ciencias 3, 28040, Madrid, Spain, (4)University of Leeds, COMET, School of Earth and Environment, Leeds, United Kingdom, (5)Natural Resources Canada, Canada Centre for Mapping and Earth Observation, Ottawa, ON, Canada
Abstract:
Geodetic data, the spatial and temporal surface expression of complex geophysical processes in the earth, is being acquired today at unprecedented rates and accuracies. Differential interferometric synthetic aperture radar (DInSAR) is a satellite remote sensing technique used extensively today for mapping ground deformation with high spatial resolution and sub-centimeter precision over large areas that is particularly useful for volcanic monitoring [Massonnet and Feigl, 1998; Rosen et al., 2000]. Here we apply the advanced Multidimensional Small Baseline Subset (MSBAS) InSAR algorithm [Samsonov and d’Oreye, 2012] to several thousand Envisat and RADARSAT-2 images from 1993–2013 and compute time series of ground deformation over the Naples Bay region of Italy. Vesuvius and Campi Flegrei are located in this area in close proximity to the densely populated city of Naples and, as a result, it is one of the most hazardous volcanic areas in the world. We obtain time series of ground deformation at high spatial and temporal resolution that span, for the first time, twenty years. Campi Flegrei underwent continuous subsidence through 1999. Uplift began in 2005, reaching approximately 13 cm by 2013. We model the observed deformation to determine source parameters for subsidence and uplift epochs [Samsonov et al., 2014]. In addition, a typical DInSAR image can contain significant signals from with several different, nonvolcanic sources. For example, we clearly observe decade-long elevation-dependent seasonal oscillations of the vertical displacement component at Vesuvius that are substantially larger than the long-term deformation rate (<0.6 cm/yr). As a result, we employ an eigenpattern decomposition technique known as Karhunen-Loeve expansion (KLE) analysis in order to identify the unique, finite set of correlated deformation patterns associated with volcanic sources at different depths [Tiampo et al., 2004; Tiampo et al., 2012]. Both the inflation and deflation mechanisms at Campi Flegrei involve large, extended sources in a layered hydrothermal system whose location is controlled by the caldera structure and stratigraphy. The temporal resolution of MSBAS approaches that of GPS daily timeseries, with superior precision and spatial resolution, making it an excellent alternative for volcano monitoring.
