UNDERSTANDING VERTICAL GROUND DISPLACEMENT FROM P-SBAS USING GETIS-ORD GI* STATISTIC

Resumen

The Differential Synthetic Aperture Radar Interferometric (DInSAR) algorithm has already shown its importance in volcanic monitoring. However, it is limited by atmospheric perturbations or temporal decorrelation, implying the existence of lowcoherence records that must be discarded. In vast studied areas, with thousands of points unevenly distributed, the interpretation of the results is usually complicated. This text presents an analysis of the vertical component variation on Tenerife island (Canary Islands), from 2005 to 2010, using Getis-Ord Gi* spatial statistic on ENVISAT DinSAR images. The ascending and descending images have been processed using the Parallel Small BAseline Subset (P-SBAS) algorithm, within ESA Grid Processing on Demand cloud environment. From Line of Sight results of both tracks, the vertical deformation speeds have been calculated over 72,207 points with high coherence (> 0.7). Finally, the Gi* statistic has been applied, obtaining a map with statistical significance, where the high values of Gi*, both positive and negative, imply the spatial clustering of likely ground movements. This map highlights areas with variable vertical kinematics on Tenerife Island, contributing to understanding of its geodynamics. The displacements obtained coincide with previous studies, evenshowing possible new relationships between some phenomena that should be considered. The Gi* spatial statistic is an efficient and quick tool to extract information in a regional scale kinematic study.