An earthquake with a magnitude of 2.5 on the Richter scale was recorded at 8:32 PM local time (9:32 PM in Lisbon) on Terceira Island, according to CIVISA. The epicenter was approximately six kilometers northeast of Santa Bárbara.
CIVISA reported that the earthquake was felt with a maximum intensity of IV on the Modified Mercalli Intensity Scale in Santa Bárbara, Serreta, Cinco Ribeiras, S. Bartolomeu, and Altares, within the municipality of Angra do Heroísmo.
The tremor was also experienced with an intensity of III/IV in Biscoitos, part of the Praia da Vitória municipality, and with intensity III in Terra Chã, S. Pedro, Santa Luzia, and Ribeirinha in Angra do Heroísmo municipality, and in Quatro Ribeiras in Praia da Vitória.
This seismic event is part of an ongoing seismic-volcanic crisis on Terceira Island, which has been ongoing since June 2022, the report added.
On the Richter scale, earthquakes are classified by magnitude as follows: 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), large (7.0-7.9), major (8.0-8.9), exceptional (9.0-9.9), and extreme (above 10).
The Modified Mercalli Intensity Scale measures the degrees of intensity and their respective descriptions.
With an intensity III, considered weak, the tremor is felt indoors, causing hanging objects to sway, with a “vibration similar to that caused by heavy vehicle traffic,” described the Portuguese Institute of Sea and Atmosphere (IPMA) on its website.
An intensity IV, categorized as moderate, results in swaying suspended objects, vibrations akin to a heavy vehicle’s passage or the impact of a heavy ball against walls. Parked cars may rock, windows, doors, and crockery may tremble, and glassware and dishes may clink. At the higher end of this intensity, walls and wooden structures may creak, according to the IPMA.
