title: Stress barriers controlling lateral migration of magma revealed by seismic tomography.
abstract: Understanding how monogenetic volcanic systems work requires full comprehension of the local and regional stresses that govern magma migration inside them and why/how they seem to change from one eruption to another. During the 2011-2012 El Hierro eruption (Canary Islands) the characteristics of unrest, including a continuous change in the location of seismicity, made the location of the future vent unpredictable, so short term hazard assessment was highly imprecise. A 3D P-wave velocity model is obtained using arrival times of the earthquakes occurred during that pre-eruptive unrest and several latter post-eruptive seismic crises not related to further eruptions. This model reveals the rheological and structural complexity of the interior of El Hierro volcanic island. It shows a number of stress barriers corresponding to regional tectonic structures and blocked pathways from previous eruptions, which controlled ascent and lateral migration of magma and, together with the existence of N-S regional compression, reduced its options to find a suitable path to reach the surface and erupt.
authors.affiliation: Institute of Earth Sciences Jaume Almera, ICTJA-CSIC, Barcelona, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Martí
authors.affiliation: Institute of Earth Sciences Jaume Almera, ICTJA-CSIC, Barcelona, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Villaseñor
authors.affiliation: Institute of Earth Sciences Jaume Almera, ICTJA-CSIC, Barcelona, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Geyer
authors.affiliation: Observatorio Geofísico Central, Instituto Geográfico Nacional (IGN), Madrid, Spain.
authors.forename: C
authors.initials: C
authors.lastname: López
authors.affiliation: Department of Earth Sciences, Geophysics, Uppsala University, Uppsala, Sweden.
authors.forename: A
authors.initials: A
authors.lastname: Tryggvason