Three earthquakes with magnitudes between 2.0 and 2.6 on the Richter scale were felt on Wednesday in Terceira, as part of the seismovolcanic crisis affecting the island, authorities announced.
According to the Azores Seismovolcanic Information and Surveillance Centre (CIVISA), the tremors were recorded at 8:25 local time (9:26 in Lisbon), 11:28 local time (12:28 in Lisbon) and 12:00. 13:00 local time (13:01 in Lisbon).
The event occurred at 12:01 local time and had a magnitude of 2.6 on the Richter scale and its epicenter was about five kilometers northeast of Santa Barbara.
“The earthquake was felt with maximum intensity IV/V (modified Mercalli scale) in Santa Bárbara and Cinco Ribeiras (municipality of Angra do Heroísmo),” CIVISA said.
The earthquake, which had the highest magnitude of the three recorded on Wednesday, was also felt with intensity IV in Altares, Raminho, Serreta, Doze Ribeiras and São Bartolomeu, with intensity III/IV in São Mateus (municipality of Angra do Heroísmo) and with intensity III in Terra Chã and Conceição (municipality of Angra do Heroísmo) and in Biscoitos (municipality of Praia da Vitória).
The Portuguese Institute of the Sea and Atmosphere (IPMA) also issued a statement on this earthquake, attributing it magnitude 2.7 and epicenter about four kilometers east-northeast of Santa Barbara.
The event “caused no personal or material damage and was felt at maximum intensity IV (modified Mercalli scale) in the parish of Cinco Ribeiras,” said the IPMA.
It was also felt with less intensity in the parishes of Santa Luzia and São Bartolomeu de Regatos.
The second event, with a magnitude of 2.4 on the Richter scale, occurred at 11:28 a.m. local time and had its epicenter approximately four kilometers northeast of Santa Barbara..
The earthquake was felt at its peak intensity IV in Santa Bárbara, Cinco Ribeiras and São Bartolomeu (Angra do Heroísmo) and in Biscoistos (Praia da Vitória), CIVISA reported.
The earthquake “was also felt with intensity III/IV in São Mateus and Terra Chã and intensity III in Posto Santo, São Pedro, Santa Luzia, Sé, Conceição, São Bento and Ribeirinha (municipality of Angra do Heroísmo),” he added.
The third earthquake felt this Wednesday in Terceira had a magnitude of 2.0, occurred at 8:26 local time, had its epicenter about three kilometers east of Serreta and was felt with maximum intensity III.
The events are part of the seismovolcanic crisis that has affected the island of Terceira since June 2022..
CIVISA on Thursday raised the alert level of the Santa Barbara volcano to V3 and that of the island’s fissure volcanic system to V1 due to seismic activity on the island.
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 respective description.”
With an intensity V, considered strong, the shock “is felt outside the home, the direction of movement can be assessed, people wake up, liquids oscillate and some drip, small objects in unstable balance move or fall,” reveals the IPMA on its website.
When there is intravenous intensity, considered moderate, “suspended objects swing, the vibration is similar to that caused by the passage of heavy vehicles or the sensation of a heavy ball hitting the walls, parked cars shake, windows, doors and dishes tremble, glass and dishes rattle or clink and at the top of this level walls and wooden structures creak.”
With intensity III, considered weak, the shock is “felt inside the house” and “hanging objects swing,” feeling a “vibration similar to that caused by the passage of heavy vehicles.”
Source: Observadora
