(ORDO NEWS) — An intense earthquake swarm shakes the Manadas volcanic fissure system in the northwestern part of São Jorge Island (pop. 8,200), Azores, Portugal. The last eruption of this volcano occurred in 1808.
According to the Center for Seismic Volcanic Information and Observation of the Azores (CIVISA), the swarm began at 17:19 LT (16:19 UTC) on March 19. Within the next 2 minutes, three earthquakes were recorded with a magnitude of 2.8 to 2.9.
The first earthquakes were felt with a maximum intensity of IV/V (modified Mercalli scale) in the parish of Manadas, with a magnitude of IV in Urzelina and Norte Grande, and with a magnitude of III in Calheta.
Over the next 24 hours, more than 700 earthquakes were recorded in the region. According to CIVISA, they were all of small magnitude and only 48 were felt.
CIVISA chief Ruy Marquez said the Manadas volcanic fissure system, which coincides with the main volcanic cones on the island, is still active and is now registering an energy release that has not been common in recent years.
“All the quakes felt in São Jorge since Saturday are of tectonic origin,” Marquez said, adding that the strongest quake was a magnitude M3.2 at 01:43 UTC on March 20. The earthquake was felt by the people of São Jorge and Pico Island.
“We are still evaluating the behavioral pattern of this seismic crisis, which is now in a phase of less energy release,” said Marquez. Currently, seismic events are moving towards the village of Velas.
“The current seismic swarm makes many think of the earthquake swarms that preceded the 2021 eruption on La Palma in the neighboring Canary Islands,” said Dr. Tom Pfeiffer of VolcanoDiscovery.
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