The three large landslides that have occurred this summer in Tenerife, the last one last Sunday on the cliffs of Los Gigantes, in the municipality of Santiago del Teide, are “normal in the Islands due to their characteristics” and “have no relationship” with the seismic swarms recorded in the Teide National Park. This is defended by two scientists who work to control natural risks in the Archipelago: Isabel Montoya, a geologist from the Spanish Geological and Mining Institute (IGME), and Itahiza Domínguez, a seismologist froml National Geographic Institute (IGN).
Isabel Montoya assures that avalanches are “normal on islands like the Canary Islands” and that the fact that these last three episodes have coincided with a period in which there have been two swarms of earthquakes on Teide is “a coincidence that has no reason to be related.” «We do not have any data that relates the landslides with the volcanic activity on Teide. They have occurred at a time of great citizen sensitivity due to the succession of small earthquakes on various specific dates in the National Park, but there is no data that points to a connection”, details the IGME researcher.
Volcanic activity can cause avalanches, as in fact happened in the days before the Tajogaite eruption on La Palma (September 19, 2021). However, these are exceptional cases in an Archipelago in which its highest islands –Tenerife, La Palma, Gran Canaria and El Hierro– register at least one avalanche of some size per week due to other factors beyond volcanic activity: strong slopes, rains, instabilities in the terrain, human action…
«The landslides are normal in islands like the Canary Islands; they are not because of the earthquakes»
The ‘awake’ volcano
Itahiza Domínguez, a member of the IGN team in Tenerife, considers that not even the detachment of June 17 – the first in this series – on the north face of the Teide cone has anything to do with the earthquakes associated with the activity of an awake volcano but that does not threaten to erupt for now. And that despite the two swarms of hundreds of earthquakes recorded on June 10 and July 13. “Earthquakes of very low magnitude, such as those recorded in the last two swarms in Teide National Park, do not produce avalanches of this type on the surface,” explains Domínguez. The seismologist clarifies that some of these landslides, especially those that drag more earth and rocks, do leave their mark on the seismic stations of the National Geographic Institute, such as the one on Teide on June 17.
That avalanche has a peculiarity: it is the first confirmed by the IGN in the volcano. Although there is evidence from the geological traces that this face of the volcano is predisposed to suffer small landslides, until now it has been difficult to confirm that they happened, since they occur “in uninhabited areas”, as Itahiza Domínguez details.
The IGN seismographs have captured these signals on several occasions that differ from the one that can emit a seismic event. “We were almost sure that they were small landslides, but it has not been until now that we have been able to confirm one in this area,” the researcher stressed on June 21, five days after the landslide. They have not been able to do so so far because there has been no evidence to prove it. However, on this occasion, the video of a neighbor in the northern area – far from the place where the landslide occurred – was able to capture the moment.
“Earthquakes of very low magnitude, like those of Teide, do not cause avalanches on the surface”
The second of these landslides in Tenerife took place on Tuesday, July 26 on a cliff in the municipality of Icod de los Vinos. There is also a video recorded by a neighbor of this episode. Twitter user Simón de la Rosa shared a video on his profile in which the detachment of part of the slope towards the sea can be seen. A few hours after the video began to go viral, Itahiza Domínguez himself shared the images, explaining that “it is not uncommon for landslides to occur on the Islands.” A day later, the IGN explained on its Twitter account that several of the island’s seismic stations also recorded this landslide.
The avalanche of Los Gigantes
The last of these avalanches happened last Sunday and has also been known by the video of a citizen recorded with the mobile phone. In the images you can see the dust that comes off the fall of earth and stones on the cliff of Los Gigantes. «The time is almost exact because I heard the rumor of the collapse and I immediately started recording. The video was saved at 14:26 but it was a moment before. Let’s see if it helps, although this one didn’t make much noise,” said Twitter user Chano Escuela (@ChanoEscuela) in one of the comments accompanying the images.
