Piton de la Fournaise is the most active shield volcano in the world. In this article we will tell you about its characteristics and the famous eruption of 2007.
The Piton de la Fournaise volcano is located on the island of La Réunion , a French overseas department in the archipelago of the Mascarene Islands, in the heart of the Indian Ocean. Located on a hotspot , with its 2632 meters high it is one of the most spectacular and active shield volcanoes in the world. Eruptions are described as effusive or Hawaiian in type, with fountains and lava flows flowing across the volcano's surface and pouring into the ocean – so the hazard is relatively low. The thing that makes the Piton de la Fournaise so famous, however, is that in the last 10 years there have been eruptions that have followed one another with a world record frequency for a shield volcano, equal to one every 9 months!
How and where was it formed?
The Piton de la Fournaise is fed by the hot spot , i.e. an area of the mantle where there is an unusual rise of magma . This acts on the crust as if it were a "blowtorch", which infiltrates between the fractures and then emerges in the open air, creating a volcano. The Réunion hotspot has been active for more than 65 million years and, in addition to the Piton de la Fournaise , also gave birth to the Lakshadweep Islands, the Maldives, the Chagos and the Mascarenes .
But how exactly was the Piton de la Fournaise formed? A huge eruption of this hot spot about 65 million years ago is believed to have originated the Deccan Traps , i.e. a series of vast flows of solidified basaltic lava (which today covers much of central India) reaching a thickness of 2 km and a total extension of 500,000 km² . This eruption occurred in conjunction with the extinction of the dinosaurs and this has therefore led to some hypotheses (still unconfirmed) about the correlation of the two events.
The memorable eruption of 2007
Among the various eruptions of the volcano, the most memorable was that of April 2007. The latter is characterized from the very first days by a violent intensity and by strong events associated with it, such as continuous earthquakes affecting the whole area around the volcano. The relatively low altitude of the eruption at around 650 meters and the velocity of the lava flows reaching the Indian Ocean in less than twelve hours after the start of the eruption were unusual, plus the lava flows reached rarely observed values with more than 100 cubic meters per second as well as lava fountain heights of over 100 meters high .
After about a month of eruption, the total volume of lava emitted was estimated at 130 million cubic meters . At the same time, the emptying of the magma chambers causes the collapse of the "Dolomieu" crater, which returns to a certain depth of about 350 meters, engulfing about 150 million cubic meters of rock. In three and a half centuries of human occupation of Réunion, volcanic phenomena of this magnitude have never been observed.
The 2007 eruption caused the island to grow 50 hectares . However, in the geological history of the Piton de la Fournaise, which is around 500,000 years old, it is probable that similar episodes have occurred on other occasions.
According to some estimates, more than 150 volcanic eruptions have been recorded on the island since the 17th century. The last dates back to September 2021 and since 2010 it has become a UNESCO World Heritage Site .
