Forecasting the size of volcanic explosions at restless volcanoes
In a paper published in Scientific Letters, a team of researchers from Carnegie Institution for Science, University of Oxford, Pennsylvania State University and Instituto Nicaraguense de Estudios Territoriales (INETER), Nicaragua, have discovered a new method for forecasting the size of volcanic explosions at restless volcanoes.
Oxford researcher Dr Mel Rodgers describes the paper: “We have been working closely with scientists at the Nicaraguan Institute of Earth Sciences (INETER) on Telica Volcano since 2009, and for many years we noticed that the volcano would go seismically quiet before the start of eruptions. Normally before a volcanic eruption we would expect an increase in seismicity, so this was something unusual – almost like Telica was holding its breath before exploding. In previous work at Telica (http://www.sciencedirect.com/science/article/pii/S0377027314003722, http://www.sciencedirect.com/science/article/pii/S0377027313002527) we have documented a long-term decline in seismic activity over the months before the start of an eruption period, but during the 2011 eruption we also noticed much shorter periods of seismic quiet in the hours before individual explosions. We decided to look systematically at these shorter periods of seismic quiet at Telica and discovered a strong relationship between the length of silence and the size of the explosion. With hydrothermally active open-vent volcanoes such as Telica, the phreatic explosions may come from sealing of gas pathways, causing pressure buildup before explosions. Our recent results now give us a quantitative relationship between the length of time of the sealing and the explosion size, allowing us to investigate the nature of this sealing process at Telica and other similar volcanoes.”
Roman, D.C., Rodgers, M., Geirsson, H., LaFemina, P., Tenorio, V., 2016. Assessing the likelihood and magnitude of volcanic explosions based on seismic quiescence. Earth Planet. Sci. Lett, 450, 20-28
Photo courtesy of INETER.