Volcanic eruption on La Palma Island, Spain

(Screeshot / Twitter / @tenerife_meteo)

For the first time since 1971, a crack opened on the Canary island of Palma, on September 19 at 15:15 local time. The speed of lava flows is 0.7 kilometers per hour.

The eruption was preceded by more than 25 thousand tremors, according to the Volcanological Institute of the Canary Islands (INVOLCAN).

The Canary Islands lie west of mainland Africa and form a chain of seven volcanic islands.

All structures are underlain by Jurassic oceanic crust, and the age of the islands increases from west to east.

This progression suggests that the archipelago was formed as a result of the slow movement of the African plate over the hotspot.

La Palma is one of the youngest and most active islands in the Canary Islands. It has two volcanic centers on its elevated Pliocene basement.

The northern complex was formed in the period from 1.7 million to 410 thousand years ago and is crowned by the Taburiente collapsed caldera.

The southern complex of Cumbre Vieja is much younger, here the oldest rocks are 125 thousand years old.

The activity of the volcano over the past 7,000 years has formed numerous cinder cones and lava flows, including a lava field at the southern tip of the island in 1678.

The last eruption of Cumbre Vieja occurred in 1971.

On September 11, a series of earthquakes began on the island of La Palma in the Cumbre Vieja region.

In the afternoon of the 19th, the number of tremors was more than 25 thousand. The maximum magnitude recorded by the seismic network of the Canary Islands was 4.2.

This is not the only seismic swarm on the island in recent years: from 2017 to 2021, the southern part of La Palma experienced up to ten series of tremors.

The main difference between the events of this September is the shallow depth of the earthquakes.

In previous years, hypocenters were located at a depth of 20 to 30 kilometers.

Within a week, the geodetic network recorded surface deformation. GPS stations recorded vertical displacements of five centimeters at the location of the earthquakes.

Researchers at the Canary Volcanological Institute interpreted this as the pressure of a magma reservoir with a volume of about 11 million cubic meters at a depth of 6-7 kilometers.

They concluded that the source of the seismic swarm is of magmatic origin and is associated with the intrusion of magma.

In the afternoon of September 19 at 15:15 local time, an eruption began in the Cumbre Vieja system.

A fissure opened in the Montaña Rajada mountains in the municipality of El Paso and began erupting fountains of lava.

(INVOLCAN / Facebook)

An hour later, a second crack appeared a hundred meters higher up the slope.

The average speed of erupting lava flows is 0.7 kilometers per hour, and the temperature is 1075 degrees Celsius.

The crack opening phase was accompanied by ash ejection.

Immediately after the start of the eruption, the satellite Meteosat-11 discovered a plume of volcanic ash drifting towards Homer Island.

The island's airport was closed during the first hours, but later reopened due to reduced emissions.

According to the Volcanological Institute of the Canary Islands, 6000-9000 tons of sulfur dioxide were released into the atmosphere on the first day.

Damage to homes and farmland has already been reported. On the morning of September 20, eight houses were buried under lava flows.

Between five and ten thousand people will be evacuated as the lava flows directly threaten the inhabitants and infrastructure of these places.

Sources:

• INVOLCAN Facebook: https://www.facebook.com/INVOLCAN/posts/303686354895694
• INVOLCAN Twitter: https://twitter.com/involcan/status/1439671523409809413?s=20

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