Updated: May 18
La Palma's Cumbre Vieja volcano eruption of 2021
Cumbre Vieja volcano is one of the most active in the Canaries. Since October 2017 until June 2021, up to 8 earthquake swarms were registered under the Cumbre Vieja volcano, the historical active volcano in the southern half of La Palma, in the Canary Islands. On September 11, 2021, a new earthquake swarm of low intensity occurred in the south of the island. It slowly migrated to the surface, with earthquakes up to around 3.5 on the Richter scale, and over 25,000 recorded in the space of 10 days. A yellow warning was issued, covering 35,000 people in the municipalities of Los Llanos de Aridane, Fuencaliente, El Paso and Villa de Mazo. On Monday 13, 1500 small earthquakes were registered in Cumbre Vieja. After a magnitude 4.2 earthquake on 19 September at 15:11 local time (14:11 UTC), the volcano started erupting and the alert was raised to its highest level—red. Lava started flowing through a crack located between El Frontón and Hoya de Tajogaite, in a valley-like landscape. A new dynamic and energetic eruption is born in Cabeza de Vaca near the Montaña Rajada, in the Las Manchas section of El Paso municipality.
La Palma's volcano opened a ninth mouth overnight 900 m north of the old ones as a magnitude 3.8 earthquake rocked the island, forcing fresh evacuations in Tacande as a new river of lava began flowing out, bringing the total number of people evacuated to 6,000. The average height of the lava flow was 6 m, meaning that any buildings in its way were easily consumed. So far, 166 homes have been destroyed, along with 250 acres of land. Within only the first day of the event, one of the volcanic vents has been constructing heaps of tephra, growing little by little and coalescing to an incipient volcanic cone.
The La Palma volcano experiences a more ‘explosive phase’ within the main fissure, with a strong increase in the amplitude of the volcanic tremor due to a slower ascent of the lava that allows gases to concentrate and explode. The volcano has been releasing a lot of energy in the form of a 4500 m tall ash plume and pyroclasts and rocks of approximately one meter being thrown up 400 m in the air, before raining and plummeting down on nearby homes. The intensity of the explosions were mistaken for a new eruptive mouth, which would be the tenth, but it has been ruled out. Although the appearance of new fissures is part of the normal process of this type of strombolian eruptions in the Islands, some remaining active and others fading while new ones appear. There have been no further deformations and bulging on the surface of the earth, which currently stands at 30 centimeters, meaning that the magmatic material that rises is what remains on the surface. The lava flows are moving slower than expected, dropping from the inicial 700 m per hour to only 4 m, but now reach up to 12 m in height, easily destroying everything in its path, including almost 200 houses and hundreds of acres of valuable farmland. The volcano eruption is the first to take place on the island in 50 years, and it is likely to last for weeks and possibly months, causing widespread damage likely to exceed the value of €400 million.
The aerosol plumes from the eruptions continue to travel along northern Africa and south Europe. The Copernicus's latest satellite-based measurements of SO₂ concentrations in the atmosphere depict that they will reach Morocco, Tunisia, Algeria, Libya including a large part of Iberian Peninsula and Mediterranean coasts of France and Italy on September 24. The highest level of sulphur dioxide (SO₂) emissions will likely occur in these areas.
The eruption is now concentrated on the new fissure near Tacande that opened yesterday. This morning, we could see tall lava fountains continuing from it as well as a new lava flow that reached approx. 1-2 km length in the area between Tacande and La Laguna.
Since the La Palma Cumbre Vieja volcano erupted 9 days ago, it has expelled 46.3 million m³ of lava, which has covered over 230 hectares of the island, completely destroying 630 buildings and infrastructures and around 20 km of roads. In the 24 days the Teneguía –another vent of Cumbre Vieja volcano– was active in 1971, it expelled 3 million m³ less than the current vent has in only a week. After the seismic energy peak recorded on Friday, and after rain of lava and ash fragments, a significant portion of the southwestern flank of the main cone collapsed on September 25th, causing a new, looser and faster lava flow. The collapse has left a narrow horseshoe-shaped breach, which continued to produce violent pulsating lava fountains generating a massive flow headed into the sea. When the lava tongue, which has a temperature of around 1,000ºC, reaches the sea, which is little over 20ºC, there are four main dangers linked to the ocean entry of lava: The sudden collapse of new land and adjacent sea cliffs into the ocean, explosions triggered by the collapse, waves of scalding hot water washing onshore, and a chemical reaction that produces a steam plume that rains hydrochloric acid and tiny volcanic glass particles. The jets of lava and individual bombs reach up to around 1,000 m in height, and the associated ash plume rises to approximately 3 km height and slowly drifts towards northeasterly directions. Around El Paso and Tacande, there is now a thick deposit of lapilli from the ongoing eruption.
The lava from the Cumbre Vieja volcano gushed for 10 days on La Palma until it poured down a cliff into the sea in the Playa Nueva area near the town of Tazacorte in the early hours of September 29. As day broke, red-hot lava protruded above the Atlantic Ocean waterline, sending clouds of steam and toxic gases into the sky. Smoke clouds billowed from the volcano and the molten rock as it flowed down Cumbre Vieja's western flank. All the people in a 2-km radius have been evacuated and a wider area is in lockdown, while all roads to the southern part of the islands had been cut off by the lava.