Geodetic Study of the 2006–2010 Ground Deformation in La Palma (Canary Islands): Observational Results

Joaquín Escayo,Mimmo Palano,Alfredo Aparicio,Eumenio Ancochea,Gema Rodríguez-Velasco,Juan F Prieto,Antonio G Camacho,José Fernández

doi:10.3390/rs12162566

Abstract

La Palma is one of the youngest of the Canary Islands, and historically the most active. The recent activity and unrest in the archipelago, the moderate seismicity observed in 2017 and 2018 and the possibility of catastrophic landslides related to the Cumbre Vieja volcano have made it strongly advisable to ensure a realistic knowledge of the background surface deformation on the island. This will then allow any anomalous deformation related to potential volcanic unrest on the island to be detected by monitoring the surface deformation. We describe here the observation results obtained during the 2006–2010 period using geodetic techniques such as Global Navigation Satellite System (GNSS), Advanced Differential Synthetic Aperture Radar Interferometry (A-DInSAR) and microgravimetry. These results show that, although there are no significant associated variations in gravity, there is a clear surface deformation that is spatially and temporally variable. Our results are discussed from the point of view of the unrest and its implications for the definition of an operational geodetic monitoring system for the island.

Highlights

The detection of the accumulation and ascent of magma from depth can have a practical application providing advance warning of future eruptive activity [1]
These are the rift-type structures and polygenic volcanic edifices such as the north–south rift of Cumbre Vieja; the areas of tensional stress caused by the continued injection of dikes on both sides of these rift structures; and calderas and valleys caused by debris avalanches such as Taburiente and Cumbre Nueva, as well as possible emerging calderas such as the hypothetical caldera resulting from the failure of the eruption of the San Juan volcano in the Llano del Banco area (Figure 1), after the 1949 eruption [31]
Micro-Gravimetry Observations To detect any possible signals related to additional masses or mass redistributions under the surface of La Palma, and taking into account the results reported in the literature [5,6,28,30,31], a micro-gravity network consisting of 12 stations was established in the SW part of the island and

Summary

Introduction

The detection of the accumulation and ascent of magma from depth can have a practical application providing advance warning of future eruptive activity [1]. A basic tool for this is to use geodetic deformation and gravity data [2,3] Their use, together with appropriate inversion techniques, allow exploring the geometry, volume and location of magmatic reservoirs along the volcano plumbing systems, helping to understand the mechanisms and characteristics of unrest and eruption [4]. Recent decades have seen an explosion in the quality and quantity of volcano geodetic data [3], in particular using satellite radar interferometry (InSAR). This technique gives the option to have high precision and high spatial resolution, spanning decades, measurements of deformation for a large numberRoemfoatecSteinvse. Older islands offer clearer evidence of longer erosional periods

Results

Discussion

Conclusion