Mount Teide or, in Spanish, El Teide, is an active though dormant volcano which last erupted in 1909 from the El Chinyero vent on the Santiago (northwestern) rift and is located on Tenerife, Canary Islands. The volcano and its surrounds comprise the Teide National Park (Parque Nacional del Teide in Spanish). The park has an area of 18900 ha and was named a World Heritage Site by UNESCO on June 29, 2007.

At 3718 m above sea level, and approximately 7500 m above the floor of the Atlantic Ocean, Teide is the highest mountain in Spain and the highest point in the Atlantic Ocean. The island of Tenerife itself is the third largest volcanic ocean island on Earth by volume. Teide is also the third highest volcano on a volcanic ocean island. It is also unstable and possibly in a more advanced stage of deformation and failure than the much publicised Cumbre Vieja. The United Nations Committee for Disaster Mitigation have designated Teide as a Decade Volcano. It is considered to be the 13th most dangerous volcano in the world due to its proximity to several major towns and the nearby city of Puerto de la Cruz.

Teide together with its neighbour Pico Viejo and Montaña Blanca forms the Central Volcanic Complex.

Name

El Pico del Teide (The Peak of Teide) is the modern Spanish name attributed to the volcano. The Lunar mountain, Mons Pico, part of the Montes Teneriffe mountain range, situated in the inner ring of the lunar mare Imbrium, was named after this 18th Century version by Johann Schröter. Prior to the 1495 Spanish colonization of Tenerife, the native Guanches referred to the volcano as Echeyde . Echeyde, in the Guanches legends, meant some sort of powerful figure leaving the volcano that could turn into hell. The Guanches believed that Echeyde held up the sky.

Formation

The stratovolcanoes Teide and Pico Viejo are the most recent centres of activity on the volcanic island of Tenerife. Tenerife is the largest (2058 km2) and highest (3718 m) island in the Canaries and has a complex volcanic history. The formation of the island and development of the current Teide volcano can be summarised into five stages, as shown in the diagram to the right.

Stage One

Similar to the other Canary Islands, and Volcanic Ocean Islands in general, the island of Tenerife was built by accretion of three large Shield Volcanoes, which developed in a relatively short period of time. This early shield stage volcanism formed the bulk of the emerged part of Tenerife. The shield volcanoes date back to the Miocene and early Pliocene and are preserved in three isolated and deeply eroded massifs: Anaga (to the NE), Teno (to the NW) and Roque del Conde (to the south). Each individual shield was apparently constructed in less than three million years and the entire island in about eight million years.

Stages Two and Three

The initial juvenile stage was followed by a period of 2-3 million years of eruptive quiescence and erosion. This cessation of activity is typical of the Canaries, for example La Gomera is currently in this erosional stage. After this period of quiescence the volcanic activity became concentrated within two large edifices; the central volcano of Las Cañadas and the Anaga massif. The Las Cañadas volcano developed over the Miocene shield volcanoes and may have reached 40 km in diameter and a height of 4500 m.

Stage Four

Around 160-220 thousand years ago the summit of the Las Cañadas I volcano collapsed creating the Las Cañadas (Ucanca) caldera. Later a fresh stratovolcano - Las Cañadas II volcano reformed and underwent catastrophic collapse. Detailed mapping indicates that the site of this volcano was in the vicinity of Guajara. The Las Cañadas III volcano formed in the Diego Hernandez sector of the caldera. Detailed mapping indicates that all the Las Cañadas volcanoes attained a maximum altitude similar to that of Teide - which is also referred to as the Las Cañadas IV volcano

Two theories on the formation of the this 16 x 9 km caldera exist.

The first is that the depression is the result of a vertical collapse of the volcano. The collapse being triggered by the emptying of shallow (at or about sea level) magma chambers under the Las Cañadas volcano after large-volume explosive eruptions.

The second theory is that the caldera was formed by a series of lateral gravitational collapses, similar to those described in Hawaii. Evidence for the later theory has been found in both onshore observations and marine geology studies.

Stage Five

Historical volcanic activity on the island is associated with vents on the Santiago or NW (Boca Gangrejo 1492, Montaña Negras 1706, Narices del Teide or Chahorra 1798 and El Chiyero 1909) and the Cordillera Dorsal or NE (Siete Fuentes and Fasnia in 1704 and 1705) rifts. Historical activity associated with the Montaña Teide - Pico Viejo stratovolcanoes occurred in 1798 from the Narices del Teide on the western flank of Pico Viejo. Eruptive material from Pico Viejo-Montaña Teide-Montaña Blanca which partially fills the Las Cañadas caldera. The last explosive eruption involving the central volcanic centre was from Montaña Blanca ~2000 BP.

The rifts form prominent ridges running NE and NW through the island from the Las Cañadas caldera. Since the collapse, eruptive products from the rifts have filled the resulting embayment with increasingly evolved (differentiated lavas) mostly of phonolitic composition and finally developed the Teide and Pico Viejo stratovolcanoes, nested in the embayment itself.

The lava flows on the flanks of Teide weather to a very thin, but nutrient and mineral rich soil that supports a diverse amount of plant species. Vascular flora consists of 168 plant species, 33 of which are endemic to Tenerife.

Historical eruptions

Teide is currently dormant, the last eruption occurred in 1909 from the El Chinyero vent, on the Santiago Rift (northwest) which is aligned in a northwest-southeast direction. Small eruptions occurred in 1704, 1705 on the Dorsal Rift (northeast). The 1706 eruption from the Montaña Negras vent on the Santiago vent destroyed the town and principal port of Garachico, plus several smaller villages. The last eruption within the Las Cañadas caldera occurred in 1798 from the Narices del Teide or Chahorra (Teides Nostrils) on the western flank of Pico Viejo (Old Peak - which is actually younger than Teide). The eruption was predominantly strombolian in style and mostly a'a lava was erupted. These lavas are visible alongside the Vilaflor - Chio road.

The explorer Christopher Columbus reported seeing "... A great fire in the Orotava Valley...," as he sailed past the Tenerife on his voyage to discover the New World in 1492. This was interpreted as indicating that he had witnessed an eruption in the Orotava Valley.

Unfortunately radiometric dating of possible lavas disproved the eruption theory. However, radiometric dating indicates that an eruption did occur in 1492 from the Boca Gangrejo vent.

About 150,000 years ago, a much larger explosive eruption occurred, probably of Volcanic Explosivity Index 5. This eruption created the Las Cañadas caldera, a large caldera, at about 2,000 m above sea level. The caldera is ~16 km across east-west and ~9 km north-south. At Guajara, on the south side of the structure, the internal walls rise as almost sheer cliffs from 2,100 m to 2,715 m. The 3,718 m summit of Teide itself, and its sister stratovolcano, Pico Viejo 3,134 m, are both situated in the northern half of the caldera, and are derived from eruptions subsequent to this prehistoric explosion.

Further eruptions are possible at some future unascertainable date, including a risk of pyroclastic flows and surges similar to those that occurred at Mount Pelée, Merapi, Mount Vesuvius, Soufrière Hills, Mount Unzen, etc. During 2003, there was an increase in seismic activity at the volcano. Many volcanoes e.g. Mount St Helens, Soufrière Hills had similar sesimic activity prior to becoming active. Such actvity is considered as being indicative of magma rising into the edifice.

Teide is considered to be unstable and has a distinctive bulge on its northern flank. This bulge is not believed to be associated with an influx of magma, but the result of a slow northwards collapse of the edifice. Seismic evidence suggests that Teide may be constructed over the headwall scarp of the infilled Icod Valley, a massive landslide valley formed by edifice failure in a similar manner to that of the Güímar and Orotava Valleys. The summit of the volcano has a number of small active fumaroles emitting sulfur dioxide and other gases including low levels of hydrogen sulfide.

Flora and fauna

Forests of Canary Island Pine (Pinus canariensis) occur from 1000-2100 m, covering the middle slopes of the volcano, and having an alpine timberline 1000 m lower than that of continental mountains of similar latitude. At higher altitudes, the Las Canadas caldera provides sufficient shelter for more fragile species such as the Canary Island cedar (Juniperus cedrus), and the Canary Island pine (Pinus canariensis) to grow.

The most dominant plant species in the Teide National Park are the Teide white broom (Spartocytisus supranubius), which has a white and pink flower; the Canary Island wallflower (Erysimum scoparium), which has white and violet flowers; and the Teide bugloss (Echium wildpretii), whose red flowers form a pyramid up to 3m in height.The Teide Daisy (Argyranthemum teneriffae) can be found at altitudes close to 3,600m above sea level. The Teide Violet (Viola cheiranthifolia) can be found right up to the summit of the volcano, making it the highest flowering plant in Spain.

These plants are adapted to the tough environmental conditions on the volcano such as high altitude, intense sunlight, extreme temperature variations, and lack of moisture. Adaptations include acquiring semi-spherical forms, acquiring a downy or waxy cover, reducing the exposed leaf area, and having a high flower production. Flowering takes place in the late spring or early summer, in the months of May and June.

The Teide National Park contains a huge range of invertebrate Fauna, over 40% of which are endemic species, with 70 species only being found in the National Park. The invertebrate fauna include spiders, beetles, dipterans, hemipternas, and hymenopterae.

In contrast, Teide national park has only a limited variety of vertebrate fauna. Ten species of bird nest in the park. These include the blue chaffinch (Fringilla teydea teydea); Berthelot’s pipit (Anthus berthelotii berthelotii); the wild canary (Serinus canaria); and a species of kestrel (Falco tinnunculus canariensis).

Three endemic reptile species are also found in the park – the Canary Island Lizard (Gallotia galloti galloti), the Canary Island wall gecko (Tarentola delalandii), and the Canary Island skink (Chalcides viridanus viridanus). The only mammals native to the Park are bats, the most common species of which is Leisler’s bat (Nycatalus leisleri). Other mammals such as the mouflon, the rabbit, the house mouse, the black rat, the feral cat, and the Algerian Hedgehog have all been introduced to the park.

Access

The volcano and its surroundings, including the whole of the Las Cañadas caldera, are protected in a national park, the Parque Nacional del Teide. Access is by a public road running across the caldera from northeast to southwest. The public bus service TITSA runs a once per day return service to Teide from both Puerto de la Cruz and Playa de las Americas. A parador (hotel) is also within the National Park along with a small chapel. The Teleférico cable car goes from the roadside at 2,356 m most of the way to the summit, reaching 3,555 m. Each car carries 38 passengers (34 in high wind) and takes 8 minutes to reach the summit. In peak season, queues can exceed two hours. Access to the summit itself is restricted; a free permit (obtainable from the Park office in Santa Cruz, Calle Emilio Calzadilla, 5 - 4th floor) is required to climb the last 200 m. Numbers are normally restricted to 150 per day

Due to the altitude, oxygen levels are lower than at sea level. This can cause people with heart or pulmanory conditions to become light headed, dizzy, develop mountain sickness and in extreme cases unconsciousness. The only treatment is to return to lower altitudes and acclimatise.

credited to wikipedia