Time Series of Surface Displacements In La Palma, Canary Islands, Determined Using Satellite Radar And GNSS Data

Abstract

We present new results on the deformation field for La Palma Island in the Canary Archipelago using A-DInSAR analysis of C-Band SAR images from ENVISAT satellite for a six-year period between years 2004 and 2010. The recent volcanic activity registered in La Palma (with seven eruptions in ca. A.D. 1480, 1585, 1646, 1677, 1712, 1949 and 1971) and the absence of any geodetic monitoring system implemented in the Island at the 90’s converts A-DInSAR studies in a basic information source for the study of surface displacements. From late 90’s several geodetic studies using GNSS, gravimetry and InSAR techniques have been carried out in the island (see Fernández et al., 2015 for a summary). In this study we updated previous radar satellite results by processing both geometries (ascending and descending), increasing the temporal coverage up to 2010 and, using a recently developed A-DInSAR processing technique, including an error estimation for the LOS mean velocity and deformation time series (“Subsidence” software, developed by the “Universitat Politècnica de Catalunya, see e.g., Blanco-Sánchez et al., 2008, and Centolanza, 2015). Our A-DInSAR results are compared with previous InSAR ones and with GNSS results obtained from several campaigns. A discussion and geological interpretation including the inversion of the results to obtain the deformation sources is also presented. Radar images have been provided by ESA through Cat.-1 13933 project.