Spanish island braces for volcanic eruption after earthquake swarm

La Palma on alert amid warning tremors could cause damage to buildings

The Spanish Canary island of La Palma is on alert for a possible volcanic eruption after several earthquakes were felt over the weekend, with officials warning that tremors could cause damage to buildings.

A 3.2-magnitude earthquake was recorded just 100 meters below the surface on Saturday, while several more tremors were detected on Sunday morning, the largest at a magnitude of 3.8.

Experts have said an eruption on the island, on the far west of the Atlantic archipelago, is not yet imminent, but there has been an intensification of earthquakes near the surface.

San Antonio Volcano. The volcanic chain last erupted in 1971 (The Independent)

The Scientific Committee of the Volcano Risk Prevention Plan said that stronger earthquakes “are likely to be felt and may cause damage to buildings”. The committee of scientific experts also signaled out a stretch of the Atlantic island's southwest coast for the risk of rockfalls.

Data from the National Geographic Institute (IGN) showed repeated earthquakes above magnitude 2 at increasingly shallow depths near the small town of El Paso.

A gas meter is seen used by the Volcanological Institute of the Canary Islands in Tazacorte on La Palma (REUTERS)

In total, more than 6,600 small earthquakes have been registered in the Cumbre Vieja area since the latest swarm activity began on 11 September.

On Sunday morning alone, the IGN said 327 earthquakes had been detected.

Two volcanologists from the Volcanological Institute of the Canary Islands collect gas samples in Tazacorte (REUTERS)

La Palma has been on alert this week after geologists reported an accumulation of molten rock under Cumbre Vieja, a dormant volcanic ridge near the island's southern tip. It last erupted in 1971.

Scientists discovered a 15-centimetre deformation of rock in Cumbre Vieja where earthquakes are occurring, indicating the presence of magma in the subsoil which is exerting pressure on the surface.

Volcano warnings are announced in accordance with the level of risk, rising through green, yellow, orange and red. Authorities decided on Monday to raise the threat level to yellow, requiring residents in at-risk zones to be prepared to evacuate.

Residents are also asked to report any sightings of gases, ash, changes in water levels or small tremors to emergency services.

The municipalities of Fuencaliente, Los Llanos de Aridane, El Paso and Villa de Mazo – home to roughly 35,000 people – are affected.

La Palma, with a population of 85,000, is known as La Isla Bonita, or the beautiful island, and is one of eight islands in the Canary Islands archipelago.

It is a popular tourist destination, attracting many German and other European travellers keen to hike its mountainous terrain.

Additional reporting by Reuters