How long will Cumbre Vieja erupt? Could land slide into the ocean and trigger a devastating tsunami? Is it worth planning a vacation in the Canary Islands now? The eruption in La Palma, which has been going on for more than two weeks – and seems to have no end – raises concerns and questions. Some of them were answered in the British Guardian by volcanologist and science journalist Robin George Andrews.
On September 19, the volcano Cumbre Vieja erupted on the island of La Palma after 50 years of silence. He sprayed lava with a temperature in excess of a thousand degrees Celsius. Since then, the river of hot magma has been traversing the island, reaching the Atlantic Ocean earlier this week. When it froze, it turned into a peninsula of at least 20 hectares. More than 800 houses were destroyed due to the incandescent rocks and ash, and about six thousand inhabitants had to evacuate. The lava flowing into the ocean poses another threat – huge quantities of toxic gases and vapors are pumped into the air, threatening the health of the local population.
The British volcanologist and science journalist Robin George Andrews answered the questions asked by many people about the eruption of the Cumbre Vieja volcano on La Palma in The Guardian.
How long will Cumbre Vieja erupt?
It is extremely difficult to say. It may stop suddenly within the next few days, or it may last for months. The average length of eruptions in La Palma is one month, but volcanic eruptions are like cats: they all have their own distinctive features, and the duration of their “panic mood” can vary.
What are the risks of the eruption of Cumbre Vieja?
The main threat is the ever-flowing lava – it has already destroyed hundreds of houses on the southwestern tip of the island, and will continue to do so as it creeps towards the coast. Ash is also a problem: it is not pleasant to inhale, especially if one has respiratory problems. But that’s not all, because ash also causes problems with visibility, burns electrical circuits, destroys car engines, pollutes water, and also destroys crops. Moreover, with the accumulation of ash on roofs, they can collapse under its weight.
Could the eruption cause a landslide into the sea with a consequent tsunami?
Volcanologists are always concerned about the sloping slopes of unstable volcanoes into the sea, which can and has already triggered a devastating tsunami. A speculative 2001 article that became the basis of an uncritical and cheap sensation-seeking documentary suggested that the catastrophic collapse of the Cumbre Vieja volcano could cause a tsunami that would flood America’s east coast in waves up to 25 meters high.
However, scientists have refuted these false theses and cooled down emotions. They now consider such a dramatic collapse of the side wall of Cumbre Vieja almost impossible. This volcano is structurally stable. It would take a huge volcanic explosion to coincide with an exceptionally severe earthquake for the slope to collapse. The probability of such a convergence is so small that it is not worth considering. But even if the mythical gods who ruled the underworld were extremely grumpy and insisted on bringing it about, there would still be nothing that could be called an apocalyptic tsunami.
What are the dangers of lava reaching the ocean? Is it dangerous?
Only if you are nearby. When hot lava meets seawater, it is extinguished to form a plume of hydrochloric acid, glassy ash and water vapor. This is definitely a problematic potion. Small explosions can also occur if the magma “collapses” and rapidly boils the seawater, which can throw volcanic debris into the air. However, these are very local hazards, so staying away from the entrance of the lava into the ocean will ensure that nothing happens to you.
Are further eruptions in the Canary Islands likely? I have a vacation booked in this area.
Volcanoes are not like bombs, one will not erupt the other even if they are close together. If another volcano erupted on a nearby island, it would be an extraordinary coincidence.
One of the possible problems for those looking to spend a holiday in the Canary Islands is the cloud of ashes coming out of Cumbre Vieja, which has forced the closure of La Palma airport for a while. If the cloud were to be found over other islands in the archipelago, their airports would also have to temporarily stop serving passengers.
Why do people settle so close to volcanoes?
About 800 million people in the world live within a hundred kilometers of active volcanoes, i.e. those that can break the dormant period and erupt at some point. Although it may seem strange to people in regions where there are no volcanoes, sometimes settling near a volcano is a voluntary choice. Volcanoes provide fertile soil attractive to farmers, are a tourist attraction and have a cultural significance.
There are also historical or socio-economic reasons for living near volcanoes or even on their slopes. Sometimes there live poorer communities, descendants of slaves who worked on the local plantations. Another reason may be the lower price of land in such a dangerous place.
Volcanoes are not the only natural threat on Earth. One might also wonder why people live, for example, in Florida, which is hit by tropical storms or hurricanes each year, or in places particularly prone to earthquakes.
Are our ability to predict volcanic eruptions increasing?
Nobody is able to predict exactly when a particular volcano will erupt and how intense. However, scientists can detect signs of an impending eruption in advance. This requires scientific and cultural knowledge of a particular volcano, accumulated over generations, especially in terms of what the volcano looks like on a daily basis.
In addition, if the volcano is monitored by a number of devices such as seismometers, gas detection tools, GPS sensors measuring ground deformation, satellites, drones – it makes it easier to detect disturbing changes in the volcano’s behavior.
The current eruption of Cumbre Vieja was expected. Before this happened, researchers noticed that the ground around the volcano was “inflated” and there were numerous earthquakes, indicating magma is breaking through the rocks towards shallow ground. After volcanologists warned of a possible eruption, authorities managed to evacuate the endangered areas before lava flows.
Main photo source: PAP / EPA / MIGUEL CALERO