No known damage caused
Two earthquakes were felt on the Azores island of Terceira on Saturday.
The first, measuring 2.1 on the Richter scale, was felt at 5.42pm local time (6.42pm in mainland Portugal), with its epicentre around three kilometres to the west-northwest of Doze Ribeira, on the island of Terceira.
The earthquake was felt with a maximum intensity of III (Modified Mercalli scale) in Serreta, said the Azores Seismic Information and Surveillance Centre (CIVISA).
A second 2.5 earthquake was registered at 8.43pm local time (9.43pm in mainland Portugal), its epicentre around three kilometres south-southwest of Altares, Terceira island.
“According to the information available so far, the earthquake was felt with a maximum intensity of IV (Modified Mercalli scale) in Raminho, Altares (Angra do Heroímo municipality) and Biscoitos (Praia da Vitória municipality),” the CIVISA statement said.
The event was also felt with intensity III/IV in Serreta, Santa Bárbara and Doze Ribeiras, and with intensity III in Cinco Ribeiras.
The Institute of the Sea and Atmosphere (IPMA) also issued a statement saying that, according to the information available so far, the earthquake “caused no personal or material damage and was felt with maximum intensity IV (Modified Mercalli scale) in the parish of Biscoitos (Praia da Vitória)”.
The two events are part of the seismovolcanic crisis that has been ongoing on Terceira island since June 2022.
According to the Richter scale, earthquakes are classified according to their magnitude as micro (less than 2.0), very small (2.0-2.9), small (3.0-3.9), slight (4.0-4.9), moderate (5.0-5.9), strong (6.0-6.9), large (7.0-7.9), important (8.0-8.9), exceptional (9.0-9.9) and extreme (when greater than 10).
The Modified Mercalli scale measures “degrees of intensity and their description”.
With an intensity of III, considered weak, the tremor is felt inside the house and the hanging objects sway, with a “vibration similar to that caused by the passage of heavy vehicles”, reveals the IPMA on its website.
When there is an intensity IV, considered moderate, parked cars sway, windows, doors and crockery shake and “glass and crockery rattle or clink”, and walls or wooden structures may creak.
Source: LUSA
