Stress barriers controlling lateral migration of magma revealed by seismic tomography

• Published in: Scientific reports Vol. 7; no. 1; p. 40757
• Main Authors: Martí, J., Villaseñor, A., Geyer, A., López, C., Tryggvason, A.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 13.01.2017; Nature Publishing Group
• Subjects: 704/2151/508; 704/2151/598; Compression; Earth science; Earthquakes; Eruptions; Humanities and Social Sciences; Magma; Migration; multidisciplinary; Rheology; Science; Science (multidisciplinary); Sea level; Seismic activity; Tomography; Velocity; Volcanic eruptions; Volcanic islands; Volcanoes; Wave velocity
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/srep40757

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.