Residents of three provinces in Galicia felt an earthquake measuring 4.6 on the Richter scale yesterday. That is an average quake that is felt like heaving passing traffic and where glasses and plates rattle.
The earthquake struck on Thursday at around 3.45 pm in the Atlantic Ocean, just off the coast of Galicia. Residents of the municipalities of Porto do Son, Fisterra and Veitureira have felt the shock at its worst. An earthquake measuring 3.4 on the Richter scale occurred in Monidariz, which falls within the ‘light’ category. Furthermore, a total of 30 minor earthquakes were recorded in Pontevedra this week.
Thursday afternoon’s average earthquake occurred three kilometers below the epicentre. This is the place on the Earth’s surface where the quake is most felt. According to social media reports, residents of the provinces of Santiago de Compostela, Lugo, and Pontevedra were particularly shocked by the earthquake.
On the Mercalli intensity scale, it was a grade IV earthquake, which is described as ‘quite strong’. This scale ranges from grade I (not felt, only recorded by seismometers) to grade XII (catastrophic). At a grade IV on the Mercalli scale, a tremor is felt by most people who are in a building but not by everyone who is on the street. At this gradation, buildings can move slightly, but the quake almost never causes damage.
In other places on the Galician coast, as well as further inland, Thursday afternoon’s earthquake had degrees of intensity III (weak; felt by a few people) and II (barely felt; felt only under unfavourable conditions).
Just under an hour before the average earthquake yesterday afternoon, there was another minor earthquake measuring 3.7 on the Richter scale and magnitude III on the Mercalli scale. This was followed by another smaller earthquake measuring 2.5 on the Richter scale.
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