Four earthquakes with magnitudes between 2.1 and 3.4 on the Richter scale were felt on Monday on the islands of Terceira and Faial, said the Seismic Information and Surveillance Center of the Azores (CIVISA).
According to CIVISA, the strongest earthquake, with a magnitude of 3.4, was recorded at 21:12 local time (22:12 in Lisbon) and had an epicenter about 39 kilometers west of Capelo, on the island of Faial.
The source said in a statement that the earthquake was felt with maximum intensity III / IV (Modified Mercalli Scale) in the parishes of Capelo, Castelo Branco and Pedro Miguel (municipality of Horta, Faial) and with intensity III in the parish of Flamengos.
The three earthquakes recorded on Monday on Terceira island occurred at 18:41 local time (19:41 in Lisbon), with a magnitude of 2.1; at 20:12 local time (21:12 in Lisbon), with a magnitude of 2.2; and at 20:13 (21:13 in Lisbon), with a magnitude of 2.4.
The quakes had an epicenter about four kilometers northeast of Santa Barbara.
Also according to CIVISA, the earthquakes on Terceira Island were felt with maximum intensity III (two) and IV (one) on the Modified Mercalli scale, in the parishes of Santa Bárbara, Doze Ribeiras and São Bartolomeu, in the municipality of Angra do Heroísmo.
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 weak, the tremor is “felt inside the house” and “the pending objects swing”, feeling a “vibration similar to that caused by the passage of heavy vehicles”, reveals the Institute of Sea and Atmosphere (IPMA) on its website.
When there is an intensity IV, considered moderate, “parked cars sway”, “windows, doors and crockery shake” and “glass and crockery rattle or clink”, and walls or wooden structures may creak, describes the IPMA.
Earthquake of magnitude 3.6 on the Richter scale felt on the island of Faial