An earthquake measuring 4.4 on the Richter scale was felt on Wednesday, December 17, at night, in Terceira, said the Azores Seismovolcanic Information and Surveillance Center (CIVISA).
The earthquake was recorded at 8:42 pm (9:42 pm in Lisbon) on Wednesday and had its epicenter approximately 39 kilometers southeast of S. Sebastião, on the island of Terceira, according to a statement from CIVISA.
“According to the available information, so far, the earthquake was felt with maximum intensity IV/V (Modified Mercalli Scale) in the eastern part of the island of Terceira”, it can be read.
“The event was still felt with IV intensity in the parishes in the western part of the island of Terceira”, he added.
The Portuguese Institute of the Sea and Atmosphere (IPMA) also released the earthquake’s record of 4.4 on the Richter scale, highlighting that, according to available information, it did not cause any personal or material damage.
“It was felt with maximum intensity IV (modified Mercalli scale) in the parishes of Fonte do Bastardo, São Sebastião and Porto Judeu (Terceira). It was also felt with lower intensity in the parishes of Feteira, Porto Martins, Santa Luzia, São Bento and Terra Chã (Terceira)”, he indicated.
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 extremes (when greater than 10).
The Modified Mercalli scale measures “degrees of intensity and respective description”.
With an intensity IV, considered moderate, “suspended objects swing, the vibration is similar to that caused by the passing of heavy vehicles or the sensation of a heavy ball hitting the walls, parked cars sway, windows, doors and crockery shake, glass and crockery rattle or clank and at the upper part of this degree the walls and wooden structures creak”, according to IPMA.
With an intensity V, considered strong, the shock is “felt outside the home, the direction of movement can be assessed, people are woken up, liquids oscillate and some leak, small objects in unstable balance move or are knocked over”.