Lava from the Cumbre Vieja volcano in La Palma remains the most destructive element of this eruption. It has already razed 906 hectares and 2,162 buildings. The last proposal is to bomb it to change its direction. It’s a good idea?
Lorenzo Pasqualini, geologist from Meteored (tiempo.com), offers his insight into the debate over the use of explosives in the Cumbre Vieja volcano.
The volcano La Palma is in it is in the sixth week of the eruption and presents important changes in its structure, in addition to intense activity. In the volcanic cone, there was a large detachment that profoundly changed its appearance and created “avenues” of lava. In addition, since last Monday, the 25th, a new eruptive mouth has been opened, the sixth, as Lorenzo Pasqualini, geologist of Meteored (tiempo.com).
Volcanic activity shows no signs of deceleration, with a soil deformation that, in areas close to the cone, reaches 10 centimeters and frequent seismic activity.
In the last few hours, between midnight and 8:00 am (Canarian time) today, Wednesday, October 27, there were 76 earthquakes in La Palma and five of them showed magnitudes greater than 4.0 mbLg. The strongest, 4.8 magnitude and with a hypocenter 35 kilometers deep, was verified last night and had maximum intensity IV on the EMS scale. It was felt on other islands in the archipelago.
Grade VI intensity indicates a “mildly harmful” earthquake experienced by most people, with possible damage to buildings and falling objects and furniture. The frequency of these earthquakes indicates that there is magmatic material trying to rise to the surface, and at the moment, along with other data, the prospect of a near end of the eruption is receding. The causes of these earthquakes could also be an underground readjustment.
If, in recent hours, attention has turned to earthquakes, which started to be felt in other islands of the Canary Islands, lava continues to be the most destructive element of this eruption. According to data provided by the European satellite system Copernicus, there are already more than 906 hectares of territory devastated by lava in La Palma and 2,162 buildings destroyed.
Bomb the lava to change its course
In the last hours, the words of the president of the Cabildo de La Gomera, Casimiro Curbelo, who suggested “Bombing” lava from military aircraft to modify the path of lava flows and thereby minimize damage to buildings, crops and infrastructure.
The idea of using bombs to slow the advance of lava is not new. In Sicily, during the Etna eruptions of 1983 and 1991-1993, this technique was used when lava threatened some inhabited centers located on the slopes of the volcano. However, the explosives were not dropped from military aircraft, they were placed precisely from the ground to modify the terrain morphology and deflect lava, after careful planning. It should be noted that Etna’s environment is very different from that of Cumbre Vieja; the Italian villages are situated at a considerably greater distance from the eruptive mouths. The difference in altitude is also important: on Etna there is a long way, both in length and in height, before the lava reaches the inhabited centers.
On May 14, 1983, explosives to change the direction of the lava, which threatened two inhabited centers, were used for the first time on the Sicilian volcano, and it is considered the first intervention of this type in Europe. Programmed by Italian volcanologists backed by Swedish explosives experts, the move was widely criticized by both other volcanologists and environmentalists. Even its results were considered “insufficient” by an important part of specialists, although there is also debate on the subject. This explosion forced lava to flow into a channel previously prepared by the Army. The preparation also faced a number of technical problems, including placing explosive material in a very hot area.
Ten years later, in the 1991-1993 eruption, explosives were used again. Initially, an attempt was made to modify the lava flow – which threatened the city of Zafferana – by building dams and launching concrete blocks from helicopters. In the end, in May 1992, the explosives were used again (7,000 kilos of used explosive) to ‘force’ the lava to enter a new, previously prepared channel. Both in the latter case and in 1983, the debate over the use of explosives to divert lava flows and their effectiveness was very intense in Italy.
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