A new study by CSIC Geosciences Barcelona (GEO3BCN-CSIC) assesses the impact that an episode of multiple extreme events in Tenerife would currently have. This publication, led by the GEO3BCN-CSIC predoctoral researcher, Marta López Saavedra, reconstructs the last great geological event in cascade that took place on the Canary Island to analyze what consequences it would have if it occurred today.
Extreme geological events are natural phenomena (volcanic eruptions, earthquakes, landslides or tsunamis) of low probability, but high impact, which represent a risk for today’s society due to their difficulty in predicting them. These episodes, which can produce chain effects and have a significant local and global impact, are potentially likely on volcanic islands, such as the Canary Islands.
This last work, published in the magazine Journal of Geophysical Research: Solid Earth, aims to predict the potential scope of a succession of cascading extreme events that could occur during a caldera-forming eruption similar to the one that occurred 180,000 years ago in the El Abrigo eruption. Joan Martí, researcher at the CSIC, Jose Luis Rubio, from the Autonomous University of Barcelona, and Karim Kelfoun, from Laboratoire Magmas et Volcans at the Université Clermont Auvergne have collaborated in the preparation of this study.
According to the results of the work, the obtained scenarios show that the main urban centers and the possible evacuation routes of Tenerife would be affected, since they could be covered by the deposits of the pyroclastic flows and probably by the ash fall.
Furthermore, the seismicity concentrated in the central part of the island during a collapse event of the central part of the volcanic edifice, such as the one that occurred 180 thousand years ago, would produce “catastrophic” effects in various parts of the island and trigger a “devastating” landslide in the Icod valley. This landslide, in turn, would produce a tsunami that would likely have a severe impact not only on the north and west coasts of Tenerife but also on other coasts of the Canary archipelago.
“At present, the volcanic system of Tenerife is not in a situation similar to that of the last caldera eruption. In fact, reaching the conditions for an eruption like that of El Abrigo can take thousands to hundreds of thousands of years ”, underlines Marta López Saavedra, main author of the article entitled Cascading Effects of Extreme Geohazards on Tenerife (Canary Islands). And, he adds, “at the current stage, the Teide and Pico Viejo volcanoes still seem too young to reach these conditions.”
López Saavedra insists that “the chances of an eruption such as El Abrigo occurring today are very low,” although he clarifies that “zero risk does not exist and, unfortunately, eruptions cannot yet be predicted.”
Investigate to prevent
“The results obtained in our study probably show the most catastrophic scenario that can be expected for Tenerife. This makes it possible to establish a maximum limit to the range of situations that may arise in order to design better risk management on this island without exceeding minor events, or falling short in the event of higher impact events ”, explains the researcher.
López Saavedra considers that this analysis will contribute to “improving the current Emergency Management Plan for the Canary Islands (PEVOLCA) by detailing the appropriate danger scenarios and optimizing mitigation actions long before any emergency occurs caused by these extreme events of multiple dangers. ”.
The researcher highlights the importance of implementing continuous improvements in disaster reduction policies by the agencies responsible for emergency management. “This implies more information and training for the population of the Canary Islands,” he stresses.
Technological advance: key to Geosciences research
To carry out this analysis, modeling software has been combined with Geographic Information Systems to simulate each event separately and, subsequently, analyze the global result of all the scenarios obtained.
The research team used the VORIS 2.0.1 software. to obtain the area potentially affected by pyroclastic density currents; a plugin for QGIS 2.14 that allows to calculate the impact of a possible earthquake; Rocscience Inc.’s SLIDE software for analyzing slope stability under seismic conditions; and finally, the VolcFlow software to simulate the propagation in space and time of the possible tsunami, as a consequence of the collision of the landslide against the ocean.