El volcán Teide se hunde

manuelmoramorales
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HUNDIMIENTO GRAVITACIONAL

Otra publicación, Phys Org, relacionada con la Universidad de Sevilla, también se ha hecho eco de la noticia y sugiere que las islas de Gran Canaria y Tenerife podrían unirse, lo cual exponen en los siguientes términos:

«Expertos de la Universidad de Sevilla y el Laboratorio de Astronomía, Geodesia y Cartografía de la Universidad de Cádiz han publicado un estudio que informa sobre el comportamiento del área geodinámica de la isla de Tenerife. Aunque el objetivo del estudio no era el comportamiento entre las dos áreas, se ha observado que Tenerife y Gran Canaria están a una distancia de cierre, lo que podría deberse a la acción de una falla entre las dos islas.

«Los valores de desplazamiento interplato detectados entre la isla de Tenerife y Gran Canaria son milimétricos, razón por la cual, dada la distancia entre las islas (aproximadamente 64 kilómetros), llevaría millones de años en unirse», dice la profesora de la universidad sevillana Cristina Torrecillas.

Desde la crisis volcánica de 2004, ha habido un hundimiento gravitacional o ajuste isostático del Teide. Este fenómeno se detectó gracias a los datos proporcionados por las estaciones de GPS ubicadas en las áreas que rodean la isla de Tenerife con valores milimétricos cada año. Por otro lado, también se ha observado que la fisura del noreste se está ampliando, posiblemente debido a la acción de una falla secundaria que aísla la cordillera de Anaga en la parte central de la isla.

Después de la crisis volcánica del Teide en 2004, provocada por una multitud de terremotos menores, surgió la necesidad de controlar la geodinámica de la isla de Tenerife, por lo que los investigadores establecieron siete puntos de referencia iniciales distribuidos alrededor de la isla. Dos de ellos se configuraron en modo de observación constante y el resto, en campañas anuales periódicas. Desde 2008, otros organismos públicos colocaron siete nuevos puntos de referencia con estaciones de observación de acceso público continuo. Juntas, estas dos redes se conocen como la red GNSS TEGETEIDE, que proporciona los datos en los que se basa este estudio.

«La vulcanología es una ciencia compleja y multidisciplinaria, pero está más que verificado que la deformación de la superficie en zonas activas generalmente precedió a eventos sísmicos o volcánicos. Esta técnica se ha aplicado en el caso de la reciente erupción en la isla vecina de El Hierro, pero no fue hasta 2015 cuando se publicó un estudio en la revista Science sobre la acción predictiva con intrusiones magmáticas», explica el investigador.»[2]

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NOTAS:

[1] «After the 2004 unrest on Tenerife (Canary Islands), the Global Navigation Satellite System (GNSS) network called TEGETEIDE was designed and deployed with seven survey mode stations to contribute to a volcanic alert system. Starting in 2008, public access data from continuous GNSS stations, managed by public institutions, were included in this network allowing measurement of ground displacement at 14 locations in Tenerife. Data acquired from 2005 to 2015 was analysed to assess ground deformation in Tenerife following the 2004 volcanic unrest. The overall ground deformation depicted compression in the central Las Cañadas Caldera possibly caused by gravitational subsidence of the high central volcanic cone. This sinking is generalised around the whole island but is less in the northeast (Anaga Massif) where we found an extension rate close to 200 strain/y that could be related to a secondary submarine fault accommodating rifting to the northeast and isolating the behaviour of this massif. At the south volcanic field (south rift), another localized area with an extensional deformation was detected, possibly resulting from the subsurface fluid migration or mass addition that caused the 2004 volcanic unrest because is located following the seismic swarm alignment along Icod Valley towards Roque del Conde massif that persists since that event. We also detected residual plate velocity indicating movement of Tenerife towards Gran Canaria that should be studied in the context of the entire Canary Islands archipelago.»(https://www.sciencedirect.com/science/article/pii/S0264370717301382?via%3Dihub)

[2] «Experts from the University of Seville and the Laboratory of Astronomy, Geodesy and Cartography at the University of Cadiz have published a study reporting the behaviour of the geodynamic area of the island of Tenerife. Although the behaviour between the two areas was not the aim of the study, it has been observed that Tenerife and Gran Canaria are closing distance, which could be caused by the action of a fault between the two islands.

«The values of interplate displacement detected between the island of Tenerife and Gran Canaria are millimetric, for which reason, given the distance between the islands (approximately 64 kilometers), it would take millions of years for them to come together,» says the University of Seville teacher Cristina Torrecillas.

Since the volcanic crisis of 2004, there has been a gravitational sinking or isostatic adjustment of Teide. This phenomenon was detected thanks to data provided by the GPS stations situated in the areas surrounding the island of Tenerife with millimetric values each year. On the other hand, it has also been observed that the northeast fissure is widening, possibly due to the action of a secondary fault that isolates the Anaga mountain range in the central part of the island.

After the Teide volcanic crisis in 2004, triggered by a multitude of minor earthquakes, the need to control the geodynamics of the island of Tenerife arose, for which reason researchers established seven initial points of reference distributed around the island. Two of these were set up in constant observation mode and the rest working in periodic annual campaigns. From 2008, other public bodies placed seven new points of reference with continuous public-access observation stations. Together, these two networks are known as the TEGETEIDE GNSS network, which provides the data on which this study is based.

«Volcanology is a complex and multidisciplinary science, but it is more than verified that surface deformation in active zones usually preceded seismic or volcanic events. This technique has been applied in the case of the recent eruption on the neighbouring island of El Hierro, but it was not until 2015 that a study was published in the journal Science on predictive action with magmatic intrusions,» explains the researcher.» (https://phys.org/news/2018-10-islands-tenerife-gran-canaria-closer.html)

 

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