For the past three days, multiple small earthquakes have shaken the Portuguese island of Sao Jorge, causing experts to warn that the series of earthquakes could lead to a stronger one or a volcanic eruption.
According to Rui Marques, head of the region’s CIVISA seismo-volcanic surveillance centre, there have been 1,800 earthquakes recorded on the volcanic island since Saturday afternoon, up from an earlier figure of 1,329.
Marques told the Lusa news agency, only 94 out of 1,800 earthquakes up to now have been felt by the population, with magnitudes ranging between 1.7 and 3.3.
There are nine islands that make up the Azores. Sao Jorge is one of nine and is home to around 8,400 people. It is part of the central group, which also includes the popular tourist destinations of Faial and Pico.
This series of small quakes, known as a swarm and which are currently causing no damage, have been recorded along the volcanic fissure of Manadas, which last erupted in 1808.
However, as a precaution, Sao Jorge’s municipalities have activated emergency plans.
“All scenarios are on the table,” said Marques while talking to Antena 1 radio station.
“On one hand, we could see an earthquake of greater magnitude that can cause some destruction. … On the other hand, we have the scenario of an eruption.”
Marques encouraged residents to remain vigilant although the earthquakes were tectonic in origin, which means they were caused by the movement of the Earth’s tectonic plates, and are not volcanic.
“We should not treat this as a purely tectonic crisis but as a seismic crisis that is taking place in an active volcanic system,” Marques said.