New perspectives and challenges on geodetic volcano monitoring using InSAR and last generation interpretation tools

Recent developments in InSAR (Interferometric Synthetic Aperture Radar) during the past decades allow to obtain high-precision, high-resolution ground deformation data with a broad spatio-temporal coverage. These large new datasets offer comprehensive insights into the deformation field and its time-evolution. Unfortunately, these new data sets cannot be fully exploited using the classical approaches for interpretation. In particular if we look for the most detailed estimation of the processes occurring in geologically active areas. Normally these classical approaches assume a priori geometries (e.g., point sources, disks, prolate or oblate spheroids, etc.) and nature of the source, and invert separately for the different sources when more than one is considered. Also, many time-series deformations in active regions are characterized by complicated patterns of ground deformation resulting from multiple natural and anthropogenic sources. In response to these challenges, we consider a new interpretation methodology which employs a combination of 3-D arbitrary sources for pressure and dislocations (including strike-slip, dip-slip, and tensile) simultaneously. This approach does not assume any a priori hypotheses regarding the deformation source’s number, nature, shape or location, providing deformation sources as 3D cell aggregations for which the inversion process automatically assigns a source type, magnitude values (MPa for pressure and cm for dislocations), position and orientation (angles of dislocation planes). The methodology inverts simultaneously ascending and descending LOS displacement time series data from InSAR, assuming the possible existence of offset values in the data sets. We show, as a way of example, a summary of the obtained results using last generation InSAR observation techniques and the new interpretation modeling to study the recent volcanic unrest and eruption in La Palma, Canary Islands, showing the obtained results.