La Palma, Canary Islands, Spain, Eruption Commenced 19 September 2021 (updated to 27.09.2021)

Good Morning!

This post has been updated as the eruption progresses. New updates will be provided in new posts.

Fig 6:  Image cropped from a photo by Eduardo Robaino, published under CC BY-SA 3.0.  Source: File:LUN 8401.jpg – Wikimedia Commons

Our thoughts are with those impacted by the eruption. While no lives have been lost, the economic damage and personal impact could be huge.

The official source for updates is IGN. You can find them on Twitter at IGN-CNIG @IGNSpain.

Update 27.09.2021

Fig 10:  The volcano taking a short break this morning, looking deceptively tranquil. The main cone is in the centre of the image.  Source: screen shot from TV Canarias:
  • The eruption is now in its ninth day. The volcano took a break for a couple of hours today, to resume with a thick ash column and a few explosions.  The new seismic swarm today may indicate that the volcano is recharging.  It would be unusual for an eruption here to be so short.
Fig 11:   Earthquake swarm 27.09.2021.  Green circles are today’s earthquakes < 3.0M; red stars are today’s earthquakes ≥3.0M; grey circles are earthquakes < 3.0M from 2017 to 26.09.2021; and cyan stars are earthquakes ≥3.0M from 2017 to 26.09.2019 (all cyan stars are in fact from the previous swarm starting 11 September 2021).  © Copyright remains with the author; all rights reserved, 2021.
  • The airport was closed for a period over the weekend while ash was cleared.
  • The cone broke in its southern section releasing a new lava which flowed over the older flow.  The new lava reached speeds of 250 – 300 metres per second. Sadly, the church and other buildings in Todoque were razed.
  • Lava may now reach the sea. It is now between 800m and 1,000m from the sea, reaching the outskirts of Tazacorte. People in San Borondón, Marina Alta, Marina Baja and La Condesa are confined to their homes with their doors and windows closed due to the risk of ash and gases. We can only imagine the stress they are under right now.
  • There have been up to 4 eruptive centres and two lava flows.  New emission points emerged in the NE section of the cone; they have since merged. 
  • On 26 September 2021, the lava covered an area of 2.62 km2, with an average thickness of 12.1 metres  a maximum thickness of 50 metres and a volume of 31 million cubic metres.  The latest estimate of damage at the time of writing is that over 500 homes and 237.5 hectares of land are now covered by lava.  18.9 km of roads have been destroyed. 1,507 hectares of land are covered by ash.
  • The Ramón Margalef is to carry out a survey of the sea floor to check for submarine emissions.
Fig 12: Drop in seismic signal and subsequent resumption.  Source: National Geographic Institute (

Armchair Volcanologist

© Copyright remains with the author; all rights reserved, 2021.

Sources as below.


  • The explosive phase, combined with the opening of new vents on the south west of the cone, has led to the evacuation of Tajuya, Tacande de Arriba and Tacande de Abaja.
  • The total number of evacuated is now 6,200.
  • Large pyroclastic materials are being ejected, and highly fluid lava with speeds of 60-80m/s is being discharged from the new vents.
  • There are fears that the main cone may collapse as a result of new vents and more explosions.  This would lead to high-speed pyroclastic flows.  You cannot outrun a pyroclastic flow.
  • The eruption column reaches 6km above sea level.
  • Although airspace is still open, Iberia, CanaryFly and Binter have suspended flights to / from La Palma, and Vueling has cancelled its Saturday flight from Barcelona to La Palma.
  • The Roque de los Muchachos Observatory has closed its telescopes to protect the mirrors from ash; it is still monitoring the gas and ash clouds from the volcano.
  • Lava covers 190 hectares; 420 buildings and 15.2 km of roads have been lost.
  • The area impacted by the volcano to be formally been declared a disaster zone.
  • It is thought that the older lava flows are slow due to the gradients they are on; they may speed up if they hit a higher gradient.
Fig 8: Increasing amplitude of the tremor, reflecting the more explosive phase.  Source for image: Instituto Geográfico Nacional (
Fig 9: Seismogram and spectrogram reflecting the increased explosive activity.  Source: Instituto Geográfico Nacional (

Sources for the update: as before.  A live webcam operated by TelevisionCanaria can be found here: DIRECTO | Erupción del volcán en La Palma – YouTube


  • The eruptive style has changed from effusive to more explosive: of the two lava flows, the northern flow has nearly stopped and the southern is c.2,100 metres from the sea, advancing at 4 metres per hour having fanned out.  It is now thought that it is unlikely that lava will reach the sea.  IGN have reported several large explosions.
  • The aviation code for La Palma has been raised from orange to red, due to gas and ash.  Airspace remains open except for two restricted areas. Airlines are advised to get flight plans checked before planes depart.
  • 2 more fissures have opened since our previous update.
  • Ground uplift is now c. 24cm.
  • 26 million cubic metres of lava have been emitted, razing 220 hectares of land and covering 180.1 hectares. The northern flow is 12m thick at the front and the southern flow, 10m thick.
  • 390 properties and 14km of roads have been destroyed.
  • Banana harvesting has been suspended in the area to allow people to collect their belongings.
  • Farmers in restricted areas require permission from PEVOLCA to irrigate their crops.
  • More than 6,000 people have been evacuated to date.
  • The Official College of Psychology of Santa Cruz de Tenerife has reminded us that those losing property to the eruption are suffering trauma; they are not helped by seeing images of this repeated multiple times on social media.

Sources: El Mundo (link below) & IGN-CNIG (link above)

We have updated our earthquake plots for the current swarm.  We have put them together in a short video.

Fig 7: Video by the author of geoscatter plots and scatter plots of the earthquake swarm from 11/09/2021 to 22/09/2021. © Copyright remains with the author; all rights reserved, 2021.


  • Air traffic is not affected; the airport remains open.  Visitors are encouraged to the island.
  • 166 homes have been confirmed as lost.  More than 6,000 have now been evacuated.
  • Land covered by lava will not be cultivatable; to date, 103 hectares of land are covered. Contaminated soil may take 20 years or more to be usable. Loss of land is expected to cause considerable poverty.
  • Lava is approaching the Todoque in Los Llanos de Aridane.
  • Several roads are closed in the vicinity of the eruption: LP-211, LP-212, LP-213, LP-215 and LP-2.
  • At the time of writing lava has not been reported as reaching the sea.  When it does, clouds of toxic and acid vapours, including chlorine, sulphur, carbon and hydrogen sulphides, hydrochloric acid, carbonic acid and CO2, will be released, forcing further evacuations.
  • SO2 emissions reached between 7,997 – 10,665 tons per day on the second day.  SO2 emissions have reached the cost of Africa.
  • It is too early to say how long the eruption will last.  The 1971 Teneguía eruption lasted 24 days and the 1949 Cumbre Vieja eruption lasted 33 days.


  • No lives have been lost or injuries reported.
  •  The airport remains open.  Air traffic is not currently affected.
  • 2 fissures had opened 200m apart, with 8 vents.
  • The temperature of the lava is over 1,000°C (last reported: 1,113°C).
  • The ground is continuing to inflate; more earthquakes are possible.
  • The south west coast of the island is at risk of landslides and rock falls.
  • The lava discharge rate is 0.7km per hour. The lava is expected to reach the ocean at c.8:00pm (has not happened yet; the lava slowed and diverted).  When the lava reaches the ocean, toxic vapours will be released due to the chemical reactions between the hot lava and sea water; the areas impacted would be Tazacorte, near Playa Nueva, Los Guirres.
  • Between 6,000 and 9,000 tons per day of SO2 were emitted on the first day.
  • 5,500 people evacuated. 
  • A 3.8M earthquake signalled the opening of a new vent (the 10th) 900m from the main vent. The new stream of lava led to the evacuation of Tacando.

Sources for the updates: El Mundo ( and AS (

19.09.2021 (original post)

An earthquake swarm which started on 11 September 2021, accompanied by uplift, resulted in PEVOLCA raising the alert level for La Palma to yellow on 13 September 2021. 

The eruption, itself, started on 19 September 2021 at 2:15pm (UTC) in Cabeza de Vaca, El Paso; the alert level is now red.  c.5,000 people have been evacuated.  To date, no lives have been reported as lost, property damage is yet to be assessed. Our thoughts are with those affected.

Fig 1a: Seismographs and spectrogram showing the onset of the eruption.  Source: Instituto Geográfico Nacional (
Fig 1b: Displacement and ground deformation measured pre-eruption. On the left, displacement is for the period 10/09/2021 and on the right, deformation is for the period June 2021 to September 2021 (to date). Source: IGN (link below).

At the time of writing, there are lava fountains and a large lava flow that is threatening people’s homes.

There are many videos on YouTube.  Here are live streams via Reuters: LIVE: Volcano erupts on La Palma in the Canary Islands – YouTube ; and, SixtyMedia: Erupción volcánica en La Palma – YouTube

La Palma

Fig 2: La Palma. Source: Google Earth

La Palma is a volcanic island with an area of 708 km2, located at the northwest end of the Canary Island archipelago above the Canary Island hotspot.  The population of the island is c85,840; 15,720 live in the capital Santa Cruz de la Palma and 20,470 in Los Llanos de Aridane. The climate is tropical semi-arid. Its economy relies on agriculture and tourism; banana cultivation is centred in the valley of Los Llanos de Aridane; and, other crops include oranges, avocados and grapes. Fishermen operate from Tazacorte, Puerto Naos and Santa Cruz de la Palma. The island has abundant flora and fauna.

The island is comprised of many volcanoes, including an extinct Pliocene – Pleistocene northern shield volcano and the active Pleistocene – Holocene Cumbre Vieja. Cumber Vieja is the most active volcano in the Canary Islands, last erupting in 1971.

The northern shield lavas comprise basanites, alkali basalts, tephrites, phonolites and trachytes, reflecting magma evolution during the shield-building stage.  The younger Cumbre Vieja volcano has more basaltic lavas.

Fig 3: Caldera de Taburiente, Bejenado and Cumbre Vieja.  Source:  Google Earth

Building the Island

The island emerged in five stages: the initial submarine-building of a seamount, followed by the creation of four volcanoes during the shield-building stage, as shown below.

Time scaleVolcanoLavas
PlioceneSea-mountBasalt, trachybasalt, phonolite, trachyte
1.7Ma -1.2MaGarafíaBasalt
1.2Ma – 0.4MaTaburienteBasalt, tephrite, phonolite
0.56-0.49kaBejenadoBasalt, tephrite, phonolite
125ka-presentCumbre ViejaBasalt, basanite, trachyte, phonolite

Garafía is covered by the later Taburiente volcano; its rocks being visible only in a few outcrops.  Around 1.2Ma gravitational collapse of its southern flank left debris avalanche deposits in the sea.

Activity at Taburiente volcano commenced without a break following the collapse at Garafía.  Its growth included the development of triple rift zones – parallel swarms of dikes at c 120° angles, indicative of magma doming.  Activity then migrated southwards.

A landslide, clearly visible on maps, occurred between the building of Taburiente and Bejenado, and was responsible for the creation of the Caldera de Taburiente.  Bejendo volcano is a small volcano that emerged to fill the collapse embayment.  Subsequent erosion enlarged the caldera.

Cumbre Vieja emerged after activity had ceased in the north.  From c. 125,000 years ago, volcanic activity built the north-south ridge until 80,000 – 20,000 years ago when activity declined.  From 20,000 – 8,000 years ago activity picked up again, focusing on the north-south rift and also north-west and north-east rifts. Activity now focuses on the north-south rift.  There is concern that another flank collapse could occur following the emergence of west facing normal faults during the 1949 eruption. 

Eruptive History

GVP records 13 Holocene eruptions for La Palma, seven of which were VEI 2s, with mild explosive activity and lava flows that caused property damage (the remaining 6 have not been assigned a VEI number).   Eruptions during the last 7,000 years have formed cinder cones and craters along the north – south axis of Cumber Vieja.  Lava flows reached the sea in 1585, 1646, 1677-78, 1712, 1949, and 1971; a large lava field emplaced during the 1677-78 eruption covers the southern tip of the island. 

GVP lists the lava types as Trachybasalt / Tephrite Basanite, Phono-tephrite / Tephri-phonolite, Phonolite, Basalt / Picro-Basalt, Trachyte / Trachydacite.

Seismic Activity

The current swarm was preceded by others: one in 2017, one in 2018, five in 2020, and three in 2021. The earthquakes in the previous swarms were deeper, between 20 and 30 km, and were less intense than the current swarm.

We have downloaded the earthquake data from IGN for 2021 to 19.09.2021 11:09 to see what has been going on.  While these are only the earthquakes that have been located (there are thousands that have not), the plots clearly indicate magma ascent. 

We do not have a precise location for the vents of the current eruption so are unable to compare it to the earthquake plots.

Fig 4: Geodensity plot and a latitude v depth (slightly rotated round) by the author of earthquakes occurring on La Palma from 1.01.2021 to 19.09.2021 11:09 by the author.  Colour in the right plot is indicative of age (red oldest, yellow newest). The current swarm started around earthquake 1051. © Copyright remains with the author; all rights reserved, 2021.
Fig 5 : Geoscatter plot and a longitude v depth (slightly rotated round) by the author of earthquakes occurring on La Palma from 1.01.2021 to 19.09.2021 11:09 by the author.  In the left plot, yellow circles denote earthquakes ≥ 2.0M and red stars, ≥3.0M. Colour in the right plot is indicative of age (red oldest, yellow newest). The current swarm started around earthquake 1051. © Copyright remains with the author; all rights reserved, 2021.

If you wish to follow the eruption as it progresses, IGN has up to date information on the eruption at La Palma on: Instituto Geográfico Nacional (

Further updates will be provided in new posts.

Armchair Volcanologist

© Copyright remains with the author; all rights reserved, 2021

Sources and Further Reading:

“Classical Geology in Europe 4: Canary Islands”, Juan Carlos Carracedo, Simon Day, Terra Publishing, 2011 (reprint).

The Smithsonian Institution’s Global Volcanism Program: Global Volcanism Program | La Palma (

Instituto Geografíco Nacional: Instituto Geográfico Nacional ( (link for La Palma)