An earthquake with a magnitude of 2.4 on the Richter scale was felt today on the island of Terceira, the Azores Seismic Information and Surveillance Center (CIVISA) said.
According to CIVISA, the quake was felt at 00:37 local time (01:37 in Lisbon) and had its epicentre about five kilometers south-southwest (SSW) of Altares, in the Terceira municipality of Angra do Heroísmo.
“According to the information available so far, the earthquake was felt with maximum intensity III/IV (Modified Mercalli scale) in the parishes of Serreta, Raminho and Altares (municipality of Angra do Heroísmo) and in the parish of Biscoitos (municipality of Praia da Vitória),” CIVISA said in a statement.
The event was also felt with intensity III in the parish of Quatro Ribeiras, in the municipality of Praia da Vitória.
The quake “is part of the seismic crisis that has been underway on Terceira Island since June 2022”.
On Sunday, CIVISA recorded three more earthquakes on Terceira island.
The first had a magnitude of 4.5 and a maximum intensity of VI. It was felt on the islands of Terceira and São Jorge at 07:19 local time (08:19 in Lisbon) and had its epicenter about one kilometer north-northwest (NNW) of Serreta.
The other two tremors, measuring 2.4 and 2.7 on the Richter scale, were felt at 16:46 local time (17:46 in Lisbon) and 16:47 local time (17:47 in Lisbon).
According to the Richter scale, earthquakes are classified according to their magnitude as micro (less than 2.0), very small (2.0-2.9), small (3.0-3.9), slight (4.0-4.9), moderate (5.0-5.9), strong (6.0-6.9), large (7.0-7.9), important (8.0-8.9), exceptional (9.0-9.9) and extreme (when greater than 10).
The Modified Mercalli scale measures “degrees of intensity and their description”.
With an intensity of III, considered to be weak, the tremor was felt inside the house and hanging objects rattled, with a “vibration similar to that caused by the passage of heavy vehicles”, reveals the Institute of the Sea and Atmosphere (IPMA) on its website.
When there is an IV intensity, considered moderate, parked cars sway, windows, doors and crockery shake and “glass and crockery rattle or clink”, and walls or wooden structures may creak.
According to the IPMA, with intensity VI, considered to be quite strong, the tremor is “felt by everyone” and “trees and bushes are visibly shaken or their noise is heard”.
