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- Carracedo, Juan Carlos, et al.
(författare)
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Geological Hazards in the Teide Volcanic Complex
- 2013
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Ingår i: Teide Volcano. - Berlin, Heidelberg : Springer Berlin/Heidelberg. - 9783642258923 - 9783642258930 ; , s. 249-272
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Bokkapitel (refereegranskat)abstract
- The island of Tenerife displays contrasted densities of population, from the densely occupied coastal zones (including tourist resorts, airport, energy facilities, etc.) to the sparsely populated forests and mountainous highlands, where most of the recent volcanic events are located. Considering the low frequency of historical eruptions (compared to Hawaii or Reunion Island for example), the assessment of geological hazards must also rely on the analysis and interpretation of prehistorical events, going back to at least the Late Quaternary. In this chapter, we review the hazards related to Teide’s volcanism, but also those from increased seismicity and from slope instability. We discuss the origin of low magnitude earthquakes, and particularly the 2004 episode of unrest. New estimates on cumulative volumes for resurfacing by lava flows during the last few thousand years are provided to serve as a tool for building a lava flow hazard map of Tenerife. Hazards related to explosive activity are also considered and although possible, with phreatomagmatic eruptions being the most likely style anticipated, explosive events are of relatively low probability at Teide in the near future.
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| 2. |
- Pérez-Torrado, Francisco José, et al.
(författare)
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Eruptive Styles at the Teide Volcanic Complex
- 2013
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Ingår i: Teide Volcano. - : Springer Berlin/Heidelberg. ; , s. 213-231
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- The wide variety of volcanic products composing the Teide VolcanicComplex (TVC) reflects an unusual assemblage of eruptive styles, with awide range of phenomena represented and only plinian and phreato-plinian styles truly lacking. This diversity is due to spatial and temporalvariations in magma composition (mafic magmas of the rift zones andfelsic magmas of the central edifice), variable magmatic volatile contentsand the interaction of magma with external water (snow, groundwater,etc.). Overall, strombolian eruptions are the most frequent eruptive styleat the TVC. Explosive eruptions of felsic material tend to be of lowvolume, for example, the largest explosive event during the Holocene, Montaña Blanca (ca. 2 ka), produced*0.2 km3DRE of phonoliticpumice during an eruptive sequence that reached explosivity of sub-plinian magnitude. Examples of phreatomagmatic activity (surge depos-its) have been described both on the northern flanks of Teide volcano aswell as from the summit area of Pico Viejo volcano. Until now moststudies on volcanic hazard assessment have focussed on ash fall and lavaflow hazards in the Canary Islands, but phreatomagmatic eruptions andtheir potential effects may have to be seriously considered as well.
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| 3. |
- Troll, Valentin, et al.
(författare)
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Pre-Teide Volcanic Activity on the Northeast Volcanic Rift Zone
- 2013
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Ingår i: Teide Volcano. - Berlin, Heidelberg : Springer Berlin/Heidelberg. - 9783642258923 - 9783642258930 ; , s. 75-92
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Bokkapitel (refereegranskat)abstract
- The northeast rift zone of Tenerife (NERZ) presents a partially eroded volcanic rift that offers a superb opportunity to study the structure and evolution of oceanic rift zones. Field data, structural observations, isotopic dating, magnetic stratigraphy, and isotope geochemistry have recently become available for this rift and provide a reliable temporal framework for understanding the structural and petrological evolution of the entire rift zone. The NERZ appears to have formed in several major pulses of activity with a particularly high production rate in the Pleistocene (ca. 0.99 and 0.56 Ma). The rift underwent several episodes of flank creep and eventual catastrophic collapses driven by intense intrusive activity and gravitational adjustment. Petrologically, a variety of mafic rock types, including crystal-rich ankaramites, have been documented, with most samples isotopically typical of the “Tenerife signal”. Some of the NERZ magmas also bear witness to contamination by hydrothermally altered components of the island edifice and/or sediments. Isotope geochemistry furthermore points to the generation of the NERZ magmas from an upwelling column of mantle plume material mixed with upper asthenospheric mantle. Finally, persistent isotopic similarity through time between the NERZ and the older central edifices on Tenerife provides strong evidence for a genetic link between Tenerife’s principal volcanic episodes.
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