About 1,100 small earthquakes have rocked one of Portugal’s central Atlantic volcanic islands in less than 48 hours, putting authorities in the Azores archipelago on alert as experts assess what they have described as an “earthquake crisis”.
Rui Marques, head of the seismo-volcanic monitoring center of the CIVISA region, told Reuters on Monday that earthquakes, ranging in magnitude from 1.9 to 3.3, had been recorded on the island of Sao Jorge since Saturday afternoon.
He said most of the earthquakes, which have caused no damage so far, have been reported along the Manadas Island volcanic fissure, which last erupted in 1808.
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 sudden increase in seismic activity is reminiscent of earthquake swarms detected before the Cumbre Vieja volcano erupted on the Spanish island of La Palma last year, about 1,400 km southeast of the Azores.
In 85 days, this eruption destroyed thousands of properties and crops.
However, CIVISA has yet to establish what the series of tremors might mean.
“It is still not possible to know the behavior of this seismic crisis,” Marques told the Lusa news agency.
CIVISA sent teams on the ground to set up two additional seismic monitoring stations on the island and to measure soil gases, an indicator of volcanic activity.
In a statement released on Sunday, the regional civil protection authority said it had already contacted local mayors and firefighters, and asked them to “stay alert” and help Sao Jorge residents if necessary.
He urged people to stay calm, stay informed and follow the recommendations of officials.
Only 63 of the 1,100 earthquakes recorded so far have been felt by people, Marques told Lusa.
“We must be a bit worried,” Marques told radio station Antena 1.
“We must not give the alert but we will be attentive to the evolution of the situation.”
Australian Associated Press