An earthquake was recorded at 12:31 local time (13:31 in Lisbon) with a magnitude of 2.7 on the Richter scale, about five kilometers east-northeast of Santa Bárbara, Terceira Island, as reported by CIVISA.
CIVISA’s statement noted that “the earthquake was felt with a maximum intensity of V (Modified Mercalli Scale) in Santa Bárbara, Cinco Ribeiras, S. Bartolomeu, Terra Chã, S. Mateus, and Posto Santo (Angra do Heroísmo municipality).”
Additionally, CIVISA reported, “it was felt with intensity IV in Doze Ribeiras, Santa Luzia, Sé, Nossa Senhora da Conceição, and S. Pedro (Angra do Heroísmo municipality) and in Biscoitos (Praia da Vitória municipality). It was also felt with intensity III in S. Bento (Angra do Heroísmo municipality) and Quatro Ribeiras (Praia da Vitória municipality).”
The seismic event is part of an ongoing seismic-vulcanic crisis on Terceira Island since June 2022, according to CIVISA.
On the Richter scale, earthquakes are categorized by magnitude as micro (less than 2.0), very small (2.0-2.9), minor (3.0-3.9), light (4.0-4.9), moderate (5.0-5.9), strong (6.0-6.9), major (7.0-7.9), great (8.0-8.9), exceptional (9.0-9.9), and extreme (above 10).
The Modified Mercalli Scale measures “degrees of intensity and respective descriptions.”
At intensity III, considered weak, the tremor is felt indoors, and hanging objects sway, with a “vibration similar to that caused by heavy vehicle traffic,” describes the Portuguese Institute for Sea and Atmosphere (IPMA) on its website.
At intensity IV, considered moderate, “suspended objects sway, the vibration is similar to that caused by moving heavy vehicles or the sensation of a heavy ball slamming into walls, parked cars rock, windows, doors, and dishes shake, glass and dishes rattle or clink, and at the high end of this degree, walls and wooden structures creak,” according to IPMA.
