Angra do Heroísmo, Azores, Nov 6, 2025 – An earthquake with a magnitude of 2.3 on the Richter scale was felt today on Terceira Island amid the ongoing seismic-volcanic crisis, as reported by the Azores Seismovolcanic Information and Surveillance Center (CIVISA).
CIVISA noted that the tremor was recorded at 7:00 a.m. local time (8:00 a.m. in Lisbon) and had its epicenter approximately six kilometers south-southeast of Altares, in the municipality of Angra do Heroísmo.
“Based on the information available so far, the earthquake was felt with a maximum intensity of IV (Modified Mercalli scale) in São Bartolomeu dos Regatos, Terra Chã, São Bento, Nossa Senhora da Conceição, and Ribeirinha (municipality of Angra do Heroísmo),” the statement indicated.
The event was also felt with intensity III in Santa Bárbara, also in the municipality of Angra do Heroísmo.
According to CIVISA, the tremor is “part of the ongoing seismic-volcanic crisis on Terceira Island since June 2022.”
The Richter scale classifies earthquakes by their magnitude as micro (less than 2.0), very minor (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 (if above 10).
The Modified Mercalli scale measures the “degrees of intensity and their respective descriptions.”
With an intensity of IV, considered moderate, “suspended objects swing, vibration resembles that caused by the passage of heavy trucks or the sensation of a heavy ball striking walls, parked cars shake, windows, doors, and crockery rattle, glass and crockery clink, and at the upper level of this degree, walls and wooden structures creak,” describes the Portuguese Institute for Sea and Atmosphere (IPMA) on its website.
With an intensity of III, the tremor is considered weak, felt indoors, and hanging objects sway, with a “vibration similar to that caused by heavy vehicles passing,” according to the IPMA.
