An earthquake was recorded at 02:39 (03:39 local time) by the stations of the Azores Archipelago Seismic Network, with the epicenter located approximately four kilometers south-southeast of Raminho (Terceira), reported the Portuguese Institute for Sea and Atmosphere (IPMA).
“No information has been received confirming that this earthquake was felt,” added the IPMA in a statement.
On Tuesday, four tremors with magnitudes between 1.8 and 3.0 on the Richter scale were felt on Terceira as part of the ongoing seismic-volcanic crisis, informed the Azores Seismo-Volcanic Information and Surveillance Center (CIVISA).
According to CIVISA, the tremors were recorded between 02:06 and 10:12 local time today (between 03:06 and 11:12 in Lisbon) and were felt in the municipalities of Praia da Vitória and Angra do Heroísmo.
CIVISA stated that the earthquakes were felt with maximum intensities of III, III/IV, IV, and IV/V (Modified Mercalli scale) in the two municipalities on Terceira Island (Praia da Vitória and Angra do Heroísmo).
The events are part of “the ongoing seismic-volcanic crisis on Terceira Island since June 2022.”
According to the Richter scale, earthquakes are classified by magnitude as micro (less than 2.0), very small (2.0-2.9), small (3.0-3.9), light (4.0-4.9), moderate (5.0-5.9), strong (6.0-6.9), major (7.0-7.9), significant (8.0-8.9), exceptional (9.0-9.9) and extreme (when greater than 10).
The Modified Mercalli scale measures the “degrees of intensity and respective description.”
With intensity V, considered strong, earthquakes are felt outside, people are awakened, liquids sway and some spill, small objects in unstable equilibrium move or fall, doors oscillate, close or open, while shutters and pictures move, and clock pendulums stop or change their oscillation state, according to the description by the Portuguese Institute for Sea and Atmosphere (IPMA) on its website.
With intensity IV, considered moderate, “suspended objects sway, the vibration is similar to that caused by the passage of heavy vehicles or the impact of a heavy ball on walls, parked cars sway, windows, doors, and dishes rattle, glass and dishes clink, and at the higher end of this degree, walls and wooden structures creak.”
According to IPMA, with an intensity of III, considered weak, the tremor is felt indoors and hanging objects sway, with a “vibration similar to that caused by the passage of heavy vehicles.”
