According to CIVISA, the first earthquake was felt on Thursday at 10:47 p.m. and the second at 1:05 a.m. today.

The first event, with a magnitude of 1.9 on the Richter scale, had its epicenter about two kilometers to the east-northeast of Serreta.

“According to the information available so far, the earthquake was felt with a maximum intensity of III (Modified Mercalli scale) in the parish of Serreta (Angra do Heroísmo municipality),” the source said in a statement.

The second recorded earthquake had a magnitude of 2.4 and an epicenter about four kilometers southeast of Raminho.

CIVISA said that “it was felt with maximum intensity IV (Modified Mercalli scale) in the parishes of Serreta, Raminho, and Altares (municipality of Angra do Heroísmo, Terceira island), and in the parish of Biscoitos (municipality of Praia da Vitória, Terceira island).”

The event was also felt with intensity III/IV in the parish of Quatro Ribeiras (Praia da Vitória).

According to CIVISA, both events are part of “the seismovolcanic crisis that has been underway 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 more significant 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 hanging objects sway, feeling a “vibration similar to that caused by the passage of heavy vehicles”, reveals the Institute of the Sea and Atmosphere (IPMA) website.

When an intensity of IV is considered moderate, parked cars sway, windows, doors, and crockery shake, glass and crockery rattle or clink, and walls or wooden structures may creak, the IPMA describes.