A seismic event was recorded at 12:30 local time (13:30 in Lisbon) with its epicenter approximately five kilometers east of Serreta, in the municipality of Angra do Heroísmo, as reported by CIVISA.
“Based on the available information, the earthquake was felt with a maximum intensity of III (Modified Mercalli scale) in Serreta and Doze Ribeiras (municipality of Angra do Heroísmo),” the report stated.
At 00:21 local time (01:21) today, CIVISA recorded another event with a magnitude of 1.8 (Richter) and an epicenter about four kilometers south-southeast of Serreta, which was felt with a maximum intensity of II/III (Modified Mercalli scale) in Doze Ribeiras (Angra do Heroísmo).
According to CIVISA, these events are part of the ongoing seismo-volcanic crisis on Terceira Island since June 2022.
On the Richter scale, earthquakes are classified according to 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 (over 10).
The Modified Mercalli scale measures “the degrees of intensity and their respective descriptions.”
With an intensity of III, the tremor is considered weak, felt indoors with swaying suspended objects, and is described as a “vibration similar to that caused by the passage of heavy vehicles,” according to the Portuguese Institute for Sea and Atmosphere (IPMA) on its website.
At intensity II, considered very weak, the earthquake is “felt by people at rest on upper floors of buildings or in favorable positions.”
