Like all of the Canary Islands, the island of Gran Canaria was also constructed via volcanic
activity.
Yet, people who live on this island are largely unaware of just how recently volcanic eruptions
have occurred.
Take for example one of the island's top tourist attractions; the Bandama Caldera.
Despite its name, this beautiful feature is not a caldera, but instead a young volcanic
explosion crater known as a maar.
It measures 1000 meters wide and 200 meters deep.
It represents the youngest volcanic eruption on the island, and originated in a massive
eruption a mere 2000 years ago.
Going around the island, there are other young features such as cinder cones, more explosion
craters, and lava flows.
In fact, Gran Canaria has produced at least 11 volcanic eruptions during the last 10,000
years.
This video will discuss this volcano and mention what its future hazards are.
The Canary islands can be found several hundred kilometers west of the coast of Morocco.
The island of Gran Canaria is the third island from the right, and has a circular shape.
The reason this island exists is due to an ancient hotspot which is also responsible
for its modern volcanic activity.
This hotspot is known as the Canary hotspot, and has been slowly moving westwards, forming
islands along the way, and creating modern eruptions such as the ongoing eruption on
La Palma.
Gran Canaria is quite an old volcano, and began forming 14.5 million years ago, when
a shield volcano began erupting onto the ocean floor.
Due to the volcano's high eruptive rate, it did not take long for it to reach the ocean's
surface, and began building an island.
This shield volcano had a series of northwest trending vents, and contained a series of
three rift zones.
Over the next 600,000 years, thousands of eruptions occurred which expanded the overall
island to approximately 80% of its modern size.
Meanwhile, at depth, this time allowed for a large body of magma to become more silica
rich, causing an immense amount of pressure to build.
Then, 13.9 million years ago, the largest known explosive eruption in all of the Canary
Islands began.
From the summit area, which was located at a different section of the island than seen
today, a towering plume of ash traveled 50 kilometers into the atmosphere.
Pyroclastic flows then raced across the landscape, covering the entire island in several meters
of superheated rock.
Within a span of 2 hours, areas within a 10 kilometer radius were buried with 30 meters
or more of rhyolite ash.
Then, due to the large volume of material erupted, an 18 x 16 kilometer section of the
volcano collapsed downwards by more than 300 meters, forming a massive caldera.
This eruption ejected more than 175 cubic kilometers of material, and was rated on the
volcanic explosivity index as a 7, causing a temporary volcanic winter.
Due to the devastation caused by this eruption, a prominent ring shaped caldera was visible
for the next several million years.
Smaller scale eruptions continued within the caldera for another 5 million years, but the
vast majority of eruptions occurred on the island's flanks.
Then, between 8.8 and 4.5 million years ago, the volcano became dormant.
During this timespan rain and wind carved away the deep valleys around the island which
we see today.
Once volcanic activity resumed, less explosive basaltic eruptions began building the modern
high point of the island, Pico de las Nieves.
In the last 10,000 years, explosive activity has continued, creating a number of cinder
cones and explosion craters spread across the northeastern two fifths of the island.
An eruption typically occurs about once every 1,000 years, meaning that more explosive eruptions
will take place in the future.
Using this hazard map, you can see which parts of the island have the highest chance of another
eruption.
If the next eruption is mildly explosive, it will create a cinder cone.
If the next eruption is highly explosive, it will create a new and large explosion crater,
resulting in pyroclastic flows travelling up to 8 kilometers away.
This was the case during the 40 AD eruption, which is when the Bandama Caldera formed,
which had a volcanic explosivity index of a 4.
I hope that you enjoyed this video!
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