Azores watch for large earthquake and eruption as island continues to shake

Satellite map shows seismic activity on the island of Sao Jorge after around 1,100 small earthquakes shook one of Portugal’s central Atlantic volcanic islands in less than 48 hours in the islands of Azores, Portugal. March 21, 2022. CIVISA (Azores Seismovolcanic Information and Monitoring Center) / Handout via REUTERS

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  • Some 1,800 earthquakes hit the island of Sao Jorge
  • Experts fear stronger tremor and volcanic eruption
  • The authorities are preparing preventive measures

LISBON, March 22 (Reuters) – A series of several small earthquakes that have rocked a Portuguese island in the mid-Atlantic for three days could trigger a stronger tremor or volcanic eruption, experts said on Tuesday, as the authorities were urging people not to go there. .

The number of earthquakes recorded on the volcanic island of Sao Jorge in the Azores archipelago since Saturday afternoon has risen to around 1,800 from 1,329 previously, said Rui Marques, head of the seismic monitoring center. -volcanic CIVISA of the region.

Only 94 of the 1,800 earthquakes, with magnitudes between 1.7 and 3.3, recorded so far have been felt by the population, Marques told Lusa news agency.

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Sao Jorge, one of the nine islands that make up the Azores, is home to around 8,400 people and is part of the central group of the archipelago, which includes the popular tourist destinations of Faial and Pico, which are also volcanic.

The series of small earthquakes, known as a swarm and which have caused no damage so far, were reported along the volcanic fissure of Manadas Island, which last erupted times in 1808.

The municipalities of Sao Jorge have activated emergency plans as a precautionary measure. Read more

“All scenarios are on the table,” Marques told radio station Antena 1. “On one side we could see an earthquake of greater magnitude which can cause destruction. … On the other side , we have the scenario of an eruption.”


Marques urged residents to remain vigilant, although he said the quakes were tectonic in origin, referring to the movement of the Earth’s tectonic plates, rather than volcanic ones.

“We shouldn’t be treating this as a purely tectonic crisis but as a seismic crisis taking place in an active volcanic system,” Marques said.

CIVISA set up two additional seismic monitoring stations on the island and deployed a team to measure soil gases, an indicator of volcanic activity. Levels appeared normal so far, Marques said.

The civil protection authority said earlier on Tuesday that it was working with other entities to prepare a response in the event of a major earthquake or eruption.

In a separate statement on Tuesday evening, he advised people to avoid all but essential travel to the leafy island to ensure authorities don’t face ‘additional strain’ if they need to help the population local.

The sudden increase in seismic activity is reminiscent of earthquake swarms detected before the eruption of the Cumbre Vieja volcano on the Spanish island of La Palma last year, about 1,400 km (870 miles) south- east of the Azores. Read more

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Reporting by Catarina Demony; Editing by Edmund Blair, Jonathan Oatis and Richard Pullin

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