Teide is one of the volcanoes Gerardo Vallelijes, a geologist who specialises in the study of volcanoes (volcanologist), is particularly interested in, and eruptions on Tenerife within historical times make it and La Palma the two most volcanically active of all the Canary Islands.
In 1492 a youngish Italian called Christopher Columbus set sail under the patronage of Her Majesty Queen Isabella of Spain in a voyage of discovery. He sailed across the Atlantic to the New World four times and during one of his voyages he reported "A great fire was seen in the Valle of the Orotava".
This was taken by many to be an eruption and was often referred to as the "Columbus eruption."
Now we have to accept that Columbus may not by modern standards been educated to the same level many of us enjoy, but nevertheless, to be in charge of a ship and indeed an expedition, required a bit more than the ability to say your name.
Columbus learnt his sailing in the Mediterranean and would have been familiar with the volcanoes of Italy, especially those that form the Aeolian Islands and in particular, the island volcano of Stromboli which has been in a continuous eruptive state for over 2000 years. The Romans referred to it as the "Light House of the Mediterranean" , so we can assume he knew the difference between a fire and a volcano.
Also in support of the fire not being volcanic, colleagues have spent many long hours searching the Valle de la Orotava for evidence of an eruption that could be dated to around the 1490's without success.
In 2007 Juan Carlos Carracedo at the Estacion de seismologica y volcanology along with others, published a paper and this indicated that they had found the site of the "Columbus eruption".
Using Radio Carbon dating methods, they had dated an eruptive centre as having been active in 1492 or thereabouts; Its location is on the Boca Tauce - Chio road and is the Boca Cangrejo or "Mouth of the Crab".
The lava from this can be traced almost down to the ocean near Puerto Santiago.
Then there followed a long period of nothing much happening volcanologically speaking that we are aware of.
On 31st December 1704 following a period of earthquakes, fissures opened along several kilometres from above Fasnia / Siete Fuentes to above the Guimar Valle. The activity is shown in records between 1704-1705.
Both Guimar and Fasnia were threatened by the lava, but fortunately the flows stopped before reaching the towns.
In 1706 on the opposite side of the island, Montana Negras above Garachico became active and lava was erupted.
This destroyed several villages and buildings before it finally over-flowed the cliffs above Garachico, entered the town, and destroyed much of the town, rendering (what was then the main port of Tenerife,) useless.
After a period of activity again it all went quiet, then in 1798 the Chahorra eruption occurred and the lavas from this can be seen from the Boca Tauce Mirador, and if you drive along the Boca Tauce - Chio road, they can be seen to have flowed down the flank of Pico Viejo - the Old Peak, which is younger than Teide.
There then followed a long, over 100 hundred years, period of no eruptive activity until in November 1909, Montana Chinyero close to Boca Cangrejo and Montana Negras erupted.
This was the last eruption on Tenerife, but almost certainly not the last.
So when will the next eruption occur?
I am sorry but my crystal ball is broken and I am unable to locate a replacement.
Next you need to remember that volcanoes are a natural unpredictable phenomena. They do not erupt to a time table, they erupt when a sufficient supply of magma is available and cannot be contained.
Mathematically speaking, there have been 6 eruptions within recorded history and the period covered is 524 years, which means on average an eruption has occurred on the island every 87 years and 4 months.
The longest period between eruptions was 1492 to 1704 or 212 years therefore if you want to pick a date in the future for the next eruption, you have as much chance of being right as someone picking next year or any year.
The rocks found in many areas of the island are mostly ignimbrites which are also known as "Fire Rock".
They form from pyroclastic density currents carrying heat as in about 600 degrees Celsius with fragmented pumice and other volcanic debris. They are formed from very explosive eruptions.
The more solid darker rocks are mostly basaltic in composition and it took me a long time to persuade the various tour companies to stop describing Teide as an extinct volcano
it is nothing of the sort, it is an active volcano in a period of dormancy.
The Tinerfeños will tell you "Teide es dorma" - Teide is asleep!".
All credit for this article goes to Gerardo Vallelijes, a volcanologist with in depth knowledge of the volcanoes in the Canaries and beyond.