In the past two decades, the public has had an increased awareness of the dangers posed
by large volcanic collapses.
A specific emphasis has been placed on the possibility of potential tsunami generating
collapses in the Canary Islands.
However, there exists another volcano in a different part of the world where such a collapse
is far more likely.
The volcano I am referring to is erupting right now, and is located on Reunion island.
The volcano is called Piton de la Fournaise, which is one of the most fascinating and beautiful
shield volcanoes I have studied.
This video will discuss this volcano, and mention what its future hazards are.
The Piton de la Fournaise volcano is located on the southeast section of Reunion island.
It makes up approximately one third of the island's landmass.
As we look around this volcanic complex, you will note a number of extremely steep cliffs
carved into the landscape.
In some locations, these cliffs are more than a kilometer in height.
They are all volcanic in origin, and formed through either caldera formation or the extension
of rift zone related stress on the island.
As such, they are a gorgeous and fascinating feature of this volcanic landscape.
The Piton de la Fournaise volcano began forming 530,000 years ago when magma related to a
nearby hotspot erupted onto the ocean floor.
Initially, this shield volcano was built on the gentle slope of the much older volcano
which makes up the majority of Reunion Island.
Eventually, Piton de la Fournaise reached the ocean surface.
It did not take long for this volcano to eventually connect to the rest of the island, thus forming
a single land mass.
As this shield volcano continued to grow in size, its center began slowly moving to the
east southeast.
Then, 250,000 years ago, a large volume eruption occurred.
As a large amount of lava erupted on the flanks of the volcano, the underlying magma chamber
drained.
This caused a 15 kilometer long section of the volcano to slump several hundred meters
to the east.
Since much of this material fell into the ocean, it generated a 240 meter high tsunami.
The aftermath of this collapse created a series of prominent cliffs which today remain in
the landscape.
Since this eruption, the ravines have continued to widen through similar forces as the volcano
continues to slip towards the east.
Two similar calderas formed 65,000 years ago, and then again in 2700 BC.
Since the last caldera collapse, the eruptions of Piton de la Fournaise have largely remained
inside the caldera rim.
These eruptions are relatively nonexplosive, and feature lava fountains, fissure vents,
and effusive flows of lava.
The majority of these erupted from the central crater, which over time has built a notable
shield volcano profile in the collapse scar.
Since 1700, the volcano has produced 182 distinct eruptions.
Since no one lives in the caldera rim, the vast majority of lava flows harmlessly travel
to the east and into the ocean.
However, about once every 45 years, a sizeable eruption occurs outside of the caldera rim
through a system of cinder cones and fissure vents.
Since 1700, 7 such eruptions have occurred.
5 of these eruptions resulted in property damage as they flowed through populated areas.
The most destructive of these eruptions occurred in 1708 and again in 1977 as lava flowed through
major cities to the north.
These flank eruptions will continue to happen, and impact populated areas about once every
64 years.
Although they are uncommon, I have outlined a map of where flank eruptions could occur.
If you live in this area, you need to have plans to evacuate with rather little notice.
The current eruption has been ongoing since April 9th of 2021.
Since this volcanic system has rather peaceful eruptions, it is safe to visit and view.
If you decide to travel towards the volcano, do NOT under any circumstances spend a prolonged
time in valleys next to lava.
Several tourists have passed out due to high levels of carbon dioxide which pool in these
low points.
With this being said, there is still the potential for the volcano to suddenly collapse towards
the sea and create another large tsunami.
However, based on its eruptive history, such an eruption occurs about once every 80,000
years.
A hypothetical future collapse should be easily predicted, as it would be preceded by a series
of large volume flank eruptions, and noticeable ground movement which would be picked up by
sensors.
Overall, this volcano is unlikely to produce a catastrophic eruption anytime soon, but
despite its low odds is more likely to do so than those volcanoes in the Canary Islands.
I hope that you enjoyed this video!
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