An earthquake was recorded by CIVISA at 17:03 local time (18:03 Lisbon time), with its epicenter located approximately four kilometers northeast of Santa Bárbara, in the municipality of Angra do Heroísmo.
The tremor was reportedly felt with a maximum intensity of IV (Modified Mercalli scale) in Santa Bárbara, Doze Ribeiras, Serreta, São Bartolomeu dos Regatos (Angra do Heroísmo municipality), and Biscoitos (Praia da Vitória municipality).
CIVISA noted that the quake is part of the seismo-volcanic crisis ongoing on Terceira Island since June 2022.
According to the Richter scale, earthquakes are categorized by their magnitude: 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), great (8.0-8.9), exceptional (9.0-9.9), and extreme (over 10).
The Modified Mercalli scale measures the “degrees of intensity and description thereof.”
An intensity of IV, regarded as moderate, is characterized by swinging of hanging objects, vibrations similar to those caused by passing heavy vehicles or the impact of a heavy ball against walls. Parked cars may rock, windows, doors, and dishes rattle, and glass and china collide or clink. At the higher end of this degree, walls and wooden structures may creak, as described by the Instituto Português do Mar e da Atmosfera (IPMA) on its website.
