Earthquake swarm detected under La Cumbre volcano, Canary Islands

Alex Glenn
Euro Weekly News
Tue, 02 Feb 2021 11:05 UTC

140 Earthquakes Detected On the Island of La Palma

140 EARTHQUAKES have been detected on the Island of La Palma under the Cumbre Vieja volcano.

The seismic swarms are being monitored by the Canary Islands Volcanological Institute (Involcan), that is operated by The Canary Islands Seismic Network. They have detected a new swarm of quakes below La Palma's Cumbre Vieja volcano.

As of around 4 am on Monday morning a grand total of 138 seismic events had already been detected. They have registered in at depths varying between 15 and 20 kilometres under the western slope the Cumbre Vieja volcano. The maximum magnitude that has been recorded so far has been 1.8 on the Richter scale.

According to Involcan both visitors to La Palma and local residents are not in any danger and should not be worried about the seismic swarm, as the depth of the earthquakes combined with the small magnitudes is not currently any cause for concern. What has been requested though is that the population keep aware of their environment and ensure they are fully aware of what to do if the volcanic activity starts to change.

In the last few years eight seismic swarms have been experienced including the current one which started on Sunday. In 2017 one swarm was experienced, and in 2018 a further one was recorded. However, in 2020 a total of five seismic swarms hit the area. For 2021 this is the first swarm to be seen.

Comment: According to a paper published in 2001, geological evidence suggests that a future eruption at Cumbre Vieja volcano could cause a catastrophic failure of its west flank and produce a 10-25m tsunami that would inundate the coast of Florida:

Cumbre Vieja Volcano -- Potential collapse and tsunami at La Palma, Canary Islands

Abstract.

Geological evidence suggests that during a future eruption, Cumbre Vieja Volcano on the Island of La Palma may experience a catastrophic failure of its west flank, drop-ping 150 to 500 km3 of rock into the sea. Using a geologically reasonable estimate of landslide motion, we model tsunami waves produced by such a collapse. Waves generated by the run-out of a 500 km3 (150 km3) slide block at 100 m/s could transit the entire Atlantic Basin and arrive on the coasts of the Americas with 10-25 m (3-8 m) height.
[...]
Figure 4. Evolution of the La Palma landslide tsunami from 2 minutes (a, upper left) to 9 hours (i, lower right). Red and blue con-tours cover elevated and depressed regions of the ocean respectively and the yellow dots and numbers sample the wave height,positive or negative, in meters. Note the strong influence of dispersion in spreading out an original impulse into a long series of waves of decreasing wavelength. See also that the peak amplitudes generally do not coincide with the first wave. Even after cross-ing the Atlantic, a lateral collapse of Cumbre Vieja volcano could impose a great sequence of waves of 10-25 m height on the shores of the Americas.
Authors:
Steven N. Ward Institute of Geophysics and Planetary Physics, University of California, Santa Cruz California, USA
Simon DayBenfield Greig Hazard Research Centre, Department of Geological Sciences, University College, London, UK