The volcanic seismology center, CIVISA, reported a tremor occurring at 10:30 a.m. local time (11:30 a.m. in Lisbon) with its epicenter approximately four kilometers east of Serreta, in the municipality of Angra do Heroísmo.
The earthquake was experienced at a maximum intensity of III on the Modified Mercalli Intensity scale in Raminho and Serreta, within the Angra do Heroísmo area, according to available data.
CIVISA stated that this tremor is part of the ongoing seismic-volcanic crisis on Terceira island, which has been active since June 2022.
On the Richter scale, earthquakes are categorized by 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 (above 10).
The Modified Mercalli Intensity scale measures the “degrees of intensity and respective description.”
An intensity of III indicates a weak tremor, felt indoors with swinging of hanging objects and a “vibration similar to that caused by heavy vehicle traffic,” as described by the Portuguese Institute for Sea and Atmosphere (IPMA) on its website.
