Description
Since the 2011-2012 submarine eruption of El Hierro Island, six periods of unrests have occurred there. Each of them has produced seismicity and ground deformation but none of them has ended in an eruption. The aim of the project is to study the volcanic sources that can be the cause of such unrests, using geodetic data, analytical models and numerical techniques. The results will be of interest not only for the studied volcano but also for the broad scientific community. They will contribute to better understand the magmatic processes and improve the management of volcanic crises. The experience of the University of Iceland, donor partner, and, in particular, of Dr. Freysteinn Sigmundsson, in the analysis of geophysical data is extremely recognized and will help to deep understand the results of the geodetic inverse modeling. The National Geographic Institute of Spain, project promoter, is in charge of the volcano monitoring and the volcanic alert in Spain since 2004. A multidisciplinary monitoring network has been deployed in the Canary Islands in order to monitor and detect the volcanic signals that come from the Earth. This first project between the National Geographic Institute of Spain and the University of Iceland aims to be the basis of a long-term collaboration between both institutions.
Summary of project results
In 2011-2012, the first volcanic eruption that occurred in Spain in the XXIst Century occurred 1.8Km south of El Hierro Island, the Canary archipelago. However, the end of the submarine eruption was not the end of the volcanic activity on the island and several magmatic intrusions occurred there producing several centimetres of ground deformation and hundreds of earthquakes. This project was proposed to better understand the characteristics of these magmatic intrusions in order to be better prepared in case a new eruption or volcanic unrest occurs again there. During the six months stay at the University of Iceland, the grantee from the Spanish National Geographic Institute together with the host institution was able to process continuous GPS data from the Spanish institute and radar SAR images from two different satellites (the Canadian RADARSAT-2 satellite and the Italian constellation of COSMO-SkyMed satellites) to obtain detailed maps of the ground deformation on El Hierro Island between 2012 and 2014. Time-series analysis of Interferometric Synthetica Aperture Radar (InSAR) were carried out to improve the coherence of the deformation maps. In addition, inverse modelling was carried out to find the main parameters of the volcanic intrusions. After performing the project, the knowledge of the characteristics of these magma intrusions as well as their effects on the ground surface lf the island has been significantly improved. Besides the work described above, field work was carried out during several weeks: a levelling campaign in Askja caldera, a gravity campaign around Langjökull glacier, and several GPS campaigns covered the area of Askja caldera, Askja surroundings, Peistareykir, Reykjanes peninsula, etc. This field work allowed learning in situ the main geodetic methods that are carried out nowadays to measure ground deformation. During the stay, the grantee attended weekly seminars at the University of Iceland as well as the annual meeting of the Futurevolc project, lead by the project partner. The results of the project are an essential information needed for the National Geographic Institute of Spain in their mandate to monitor the volcanic activity in Spain. One article has been published with the participation of the beneficiary (New Insight into the 2011-2012 unrest and eruption of El Hierro Island (Canary Islands) based on integrated geophysical, geodetical and petrological data, edn, Vol.58. Two more articles are in preparation.
Summary of bilateral results
This project brought together the volcanology departments of the National Geographic Institute of Spain, the Complutense University of Madrid, and the University of Iceland. This is the first time these groups cooperated. In particular, the collaboration was made possible by Dr. Freysteinn Sigdmunson and the group of deformation and seismology at the University of Iceland. The extensive experience of Dr. Freysteinn Sigmundsson and the University of Iceland in managing and monitoring the Icelandic volcanic activity with 32 active volcanic systems in their country have been remarkable and useful for the National geographic Institute of Spain, where his volcanology group is relatively new, founded in 2007. Moreover, the volcanic activity in El Hierro island helped to better understand the volcanic processes that occur at depth. For example, there is a close relationship between El Hierro magma intrusions and Eyjafjallojökull volcano activity, the volcano that closed the air traffic in Europe in 2010. Partners expect to maintain this collaboration in the future.