About 1,300 small earthquakes they rocked Sao Jorge, one of Portugal’s volcanic islands in the Atlantic as of the weekend, prompting authorities to activate a contingency plan while experts predicted a “seismic crisis“.
Rui Marques, head of the Azores archipelago’s Civisa seismicvolcanic monitoring center, said on Monday March 21 that the earthquakes were of magnitude between 1.9 and 3.3, have been recorded on Sao Jorge Island since the afternoon of March 19. Only a little more than 100 of the 1,100 earthquakes recorded so far have been felt by the population, Marques said. The expert added that most of the earthquakes that have not caused damage so far have been reported along the volcanic fissure of the Isle of Manadas, which last erupted in 1808.
One of the nine islands in the Azores, Sao Jorge has a population of around 8,400 and is part of the archipelago’s core group, which also includes the popular tourist destinations of Faial and Pico, which are also of volcanic origin.
“We are facing a seismicvolcanic crisis” that has raised fears of “a strong earthquake” or “a volcanic eruption‘ Rui Marques explained to the Publico newspaper. However, Civisa has yet to determine what this series of shocks could mean. “It is not yet possible to know the behavioral pattern of this seismic crisis,” Marques said. The Portuguese meteorological institute Ipma states that the origin of this seismic activity “could be related to an increase in magma”.
Luis Silveira, mayor of the municipality of Velas, where a large part of the population of Sao Jorge lives, described it as a preventive measure and signed a document activating a contingency plan. Civisa dispatched ground crews to set up two additional seismic monitoring stations on the island and measure ground gases, an indicator of volcanic activity.
In a statement on Sunday, March 20, the regional disaster management agency said it had already contacted local mayors and firefighting units, asking them to “stay alert” and help the people of Sao Jorge if needed. He urged people to remain calm and follow the authorities’ recommendations. “We have to be a little worried,” he told radio station Antena 1. “We shouldn’t sound the alarm, but we will closely monitor the development of the situation.”
Portuguese Prime Minister Antonio Costa said he was in constant contact with the President of the Autonomous Region of the Azores, José Manuel Boilero, to follow the evolution of the situation.
The sudden surge in seismic activity is reminiscent of the seismic swarms detected before the Cumbre Vieja volcano erupted last year on the Spanish island of La Palma, about 1,400 km southeast of the Azores. In 85 days, this eruption destroyed thousands of properties and buildings.