With the awakening of the La Palma volcano, it reactivated an old fear, which has accompanied palmeros for decades. Is the volcanic edifice of Cumbre Vieja stable? Could the northern flank of the island collapse? Experts feared a "catastrophic collapse" of part of the cone, which did not occur. The cracks of the last days of activity could have been the key that avoided the tragedy.
The stability of the western flank of the island has been studied for decades, with assessments that include the estimated destructive capacity that this landslide would have: A large tsunami that would cross the Atlantic. Experts have cleared up this concern in society in a recent publication by researchers Mercedes Ferrer, Senior Researcher at the IGME-CSIC, and Luís González de Vallejo, Honorary Professor at the Complutense University of Madrid (UCM) and director of the Volcanic Risk area of the The Volcanological Institute of the Canary Islands (Involcán) in the prestigious magazine 'Science', has confirmed that the Cumbre Vieja building is mechanically stable in the long term.
This building is firm in most of the human scale, which means that it will survive the current palm trees, regardless of the volcanic-structural characteristics associated with the recent eruption of Cumbre Vieja in 2021, which aroused this historical threat, they have said.
With the eruption of the unnumbered volcano in Cumbre Vieja, the possibility of a partial collapse was planted, a 'collapse' of part of the cone that ultimately did not occur on a large scale. The eruption, which began on September 19, 2021 and ended after 85 days and 8 hours, was the largest and most voluminous eruption on La Palma. With more than 200 million cubic meters of lava and a VEI3 explosiveness index, they set off the alarms, as scientists recall in the journal 'Science'.
On October 3, 8 and 23, 2021, part of the cone collapsed, creating new flow routes and erratic blocks the size of three-story buildings that came down the slopes. The idea of a general collapse was diluted on the island.
As explained in the scientific paper, a key research question remains why this eruption did not create a catastrophic collapse of the volcano's flank, as perhaps expected. The answer may be linked, it has its different volcanic-tectonic characteristics and, in particular, it has an "irregular system of cracks that were sheltered during the last phase of the eruption."
These cracks were seen by society, thanks to the monitoring and information shared day by day by seismologists, geologists and volcanologists on the ground. The director of IGN, María José Blanco, like her colleague Carmen López and Stavros Meletlidis read in her Pevolca diary that "she could see a partial collapse of the cone" and before the appearance of fissures they called for calm, anticipating that realizing it would be towards the interior of the cone, and not the other way around.
The cracks and fractures were registered in the last days of the volcano, at the beginning of December. At that time, the director of the Central Geophysical Observatory of the National Geographic Institute (IGN) reported on the scientific committee of Pevolca (Canary Islands Volcanic Emergency Plan (Pevolca), Carmen López, explained that they could evolve and cause landslides and collapses inside the Crater That is, with a local effect that would not damage the stability of the volcanic building, since they only appeared in the upper zone of the northeast sector of the main building.
The secondary cone of the La Palma volcano has several fractures in its building in the northeast part. pic.twitter.com/DJL6fUTtZF
— 🏳️🌈Rubén López 🇪🇸 (@rubenlodi) December 6, 2021
Due to good monitoring effort, this eruption will allow the testing of a wide range of scientific ideas, from the importance of a possible 436-year supercycle of eruptions of decreasing duration to the use of geophysical observations to understand how magma is stored and migrates. dent of a vertically extending upper mantle and crustal magmatic system. These types of magmatic and volcanological information will transform volcanic eruption risk assessment and long-term planning.
Part of this valuable information has been transferred by the Involcán teams to the island of São Jorge in Azores (Portugal), who traveled to the island to help monitor and follow up the activity in the face of the possibility of an imminent eruption,
