Through channels most convolute and mysterious a request came into my hands for a guide to the volcanism of Lanzarote for a young man called Luke. Feel the volcanic force, young Luke!
The Canary Islands
As Africa and South America broke apart and the South Atlantic started to form 106 million years ago there was a lot of volcanism along the entire line. One of these places was where the Canary Islands would form.
Most of that old volcanism died down and today only the Canary Islands Hotspot and the Cameroon Volcanic Line remains. Both are upwellings of deep warm mantle material that easily melts and creates volcanoes to form above them.
The Canary Islands consist of 7 volcanic Islands, from east to west these are Lanzarote, Fuerteventura, Gran Canaria, Tenerife, La Gomera, La Palma and El Hierro. From east to west there is a trend with the islands becoming younger as you go.
Fuerteventura is oldest with its 22 million years and youngest is the 1-million-year-old El Hierro. Lanzarote is the second oldest island at 15.5 million years.
Many of the older islands had an initial phase of intense volcanism as the islands formed, before they for reasons unknown stopped erupting. Fuerteventura stopped erupting 11.8 million years ago and restarted erupting again 5.1 million years ago and the same figures for Lanzarote is 5 million years ago with a renewal 3.7 million years ago.
The reason for the pauses is one of the major mysteries in volcanology and hopefully some young volcanologist will solve it in the years to come.
The island of Lanzarote is a large volcano, counted from the bottom of the ocean it is 3 200 meters high, even though the island is fairly low. Large parts of the island have been eroded by weather and wind, and it is only about half of the island that is covered in young volcanism.
After the volcanic break the eruptions has been small and far between up until 22 000 years ago when eruptions both became larger and more frequent.
Locally the volcano is called Timinfaya, but that is not entirely correct since the entire island is a rift volcano. In fact, the volcano is larger than the island. Between the island of Fuerteventura and Lanzarote the water is only 40 meters deep. That means that during the last ice age when a lot of water was bound as ice and the ocean level was lower, both islands where connected in a very large island that was 200 kilometres long and covered 5 000 square kilometres.
The reason for this is that both Lanzarote and Fuerteventura is sitting on a crack in ground that is called “The African Rift”. It is through that crack in the ground that magma rises and comes out in large eruptions as lava.
It is believed that one day there will be a large eruption between the islands and that they will once again become connected.
Eruptions in Lanzarote tend to happen at many spots in the island, and each spot tend to erupt once or twice before moving on to a new place. This is of course a problem for the locals and the people who work with predicting eruptions.
If an eruption would be coming, the volcanologists would be able to warn about it in advance, but there would be a problem telling where on the island the eruption would happen. And since nobody wishes for a volcano to come through the ground under their house, the authorities would have to evacuate a lot of people before the eruption started.
Volcanism at Lanzarote started approximately 35 million years ago, but the first twenty million years was below the surface of the water. During this time, there must have been thousands of eruptions to build up this giant of a volcano.
The sub-surface activity was mainly happening at the centre of the current island. As volcanism started to form the island most of the action was instead at the southern end of the island in the beginning.
This island forming eruption was truly colossal and built up a very large conical island with softly sloping sides, something that is called a shield volcano. It is estimated that this eruption lasted for 1 million years. As such it is the eruption that lasted the longest time that we know of. Almost all of this ancient volcano is now destroyed by wind and waves. This ancient island of Lanzarote is called Los Ajaches. Remnants of it can still be found hidden under more modern layers at the southern end of the island.
After that there was minimal volcanism at Lanzarote for 3 million years before the Famara Massif was constructed. This part is still the highest area in Lanzarote at 671 meters above ocean level. This eruptive sequence consisted of many large and small eruptions over 6.4 million years.
These two islands were in turn glued together by volcanism that occurred at the centre of today’s Lanzarote. This much smaller volcanism occurred during the latter half of the formation of the Famara Massif.
After that further volcanism has kept the island in shape and has lately been building up the size further. Some of these eruptions have been pretty large, but not on the same scale as the initial eruptions.
The Great 1730 Timanfaya eruption
During the last 2 000 years, almost all large non-explosive volcanic eruptions has happened in Iceland. One of the few exceptions to this rule can be found at Lanzarote. On the 1st of September in the year of 1730 a 13-kilometre-long fissure opened up in the central parts of the island in what is today known as the Timanfaya National Park.
In the beginning lava fountained up along across the entire length of the fissure, but soon the activity became centred around a few craters. The lava flow was so large that when it entered the ocean it did so over a 20-kilometre-long stretch of the coast. It must have been an amazing sight watching lava falls pour down over the cliffs with huge clouds of steam forming as the molten rock superheated the water.
This is also the longest historical eruption in the Canary Islands, it lasted for almost six years, until it ended on the 16th of April 1736. By the time it was finished, almost 5 cubic kilometres of lava had poured out of the tormented ground, covering 60 square kilometres of ground.
The 1824 eruption
The 1824 eruption is the last eruption in Lanzarote, at least so far. It occurred in the northern parts of the island. It started on the 31st of July 1824 and was concentrated at the Volcan Nuevo, Tinguaton and El Clerigo Duarte volcanic centres.
Even though this eruption was quite a bit smaller, it is still a very interesting to visit since it gives a good idea of how a future volcanic eruption could reshape the island.
The highest point in Lanzarote (671 meters) is the remnants of a volcanic eruption that was too hard for weather and wind to destroy. It is called Peñas de la Chache and is in the north. It is a remnant from the Famara Massif.
Another nice part to go and visit is the largest remaining volcanic crater, it is called Volcán de la Corona and is in the middle of the island. This volcano erupted 21 000 years ago and created a lot of new land and some of the largest volcanic tubes on the planet. The eruption was one of the largest effusive eruptions in the last 100 000 years, only to be rivalled by the Icelandic volcanism.
Visiting the Timanfaya National Park is a really good idea since one can still to this date see residual effects of the truly awesome 1730 eruption.
Cueva de los Verdes Lava Tube – This is a must to visit. It is the world’s largest intact lava tube. It came from another large eruption that occurred 21 000 years ago from Monte Corona. The lava tunnel is 6 kilometres long below ground. On top of that it extends a further 1.5 kilometres below the surface of the ocean, a feature called Tunnel de la Atlantida, a heaven for divers. This is in my opinion a must for any volcano friend. Just imagine standing in this great cave thinking about all the lava that gushed through the tunnel. It is one of the natural wonders of the world.