Next January, a group of experts, who belong to several international scientific institutions and will be directed by the researcher Jesús M. Ibáñez Godoy (Andalusian Institute of Geophysics of the UGR), will develop the largest campaign on seismic tomography undertaken to date, in Tenerife, Spain. The objective is to determine the internal structure of the volcano system in Tenerife to nearly 10 km in depth.
The team, which consists of 40 scientists, will install seismographs throughout the island of Tenerife, with particular interest in the area of Cañada-Teide-Pico Viejo volcano. Nearly 150 seismic stations will record, on the one hand, natural signals, which come from the volcano seismicity itself, and, on the other hand, artificial signals from the ship Hesperides. For this latter study, the Hesperides will approach the island to 2 km off the coast. The vessel will generate around 14,000 signals for two weeks, which will be received by the seismic stations. Ibáñez indicates that this journey will be the equivalent of recording almost 3 million small earthquakes which are imperceptible to the population.
A question of speed
Thanks to data recorded, it will be possible to draw a 3D image of the area speed (it would be the equivalent to a T.A.C. in human beings) that may be related to an earth model or structure. According to the researcher, from an earth model of the area it is feasible to ascertain the trajectory of the signals. The time it takes for the signal to travel that distance to receiver can be also determined. “Knowing the travel time and the distance, the speed of the signal can be determined. In this way, a lower speed indicates the presence of magma, water, gas, or fragmented rock material in that area. On the contrary, a higher speed shows the presence of cold or compressed magma or much consolidated material.
This research is highly useful because it provides in-depth information on the internal structure of volcanoes. This study will also enable reliable seismic location and the formulation of evolution models of the volcano system. The data will also be suitable for systems of alert and, above all, for reinforcing the knowledge of that area.
A harmless experiment
All the experiments to be performed within the project in Tenerife are only slightly invasive. That is, seismic stations will be buried in small holes under the earth’s surface. These holes will be filled in when the research finishes, in order to maintain the site as it was found at the beginning of the study. It has been widely proven that the Hesperides activity in the sea is harmless for marine life, according to previous experiments performed in other places with high environmental protection, such as the Antarctic island of Deception.
This project, which is expected to start on January 8th, 2007 and finish the 30th of the same month, involves the following centres: the University of Granada as the research coordinator, the Geophysics Centre of the Canary Islands, the Department of Geography of the University of La Laguna, and the CSIC (the Spanish National Research Council) And at the international level: the University of Liverpool (the UK), the National Institute of Geophysics and Volcanism (Italy), the University College of Dublin (Ireland), the USGS (USA), the University of Colima (Mexico), and the Universities of Buenos Aires and La Plata (Argentina). The Institute of Technology and Renewal Energies (ITER) of Tenerife will also participate in the research.
Reference:
Prof. Jesús M. Ibáñez Godoy. Andalusian Institute of Geophysics. University of Granada.
Phone: +34 958 242 733. Mobile: +34 629 571 353. Email: ibanez@iag.ugr.es
