The earthquake, with a magnitude of 5.3 on the Richter scale, was recorded at 05:11 on Monday at the stations of the Seismic Network of the mainland, with an epicentre around 60 kilometres west of Sines.

“In terms of magnitude, and considering an area with a radius of 100 kilometres around the epicentre, this is the 10th largest earthquake to have occurred since the 16th century. This area being very marked by the occurrence, in 1858, of a particularly important historical earthquake, known as the Setúbal earthquake and which had a magnitude of 7.1”.

The IPMA also stressed that in the “accelerometric station closest to the epicentre of the earthquake of 26 August, the highest ground motion acceleration values ​​ever recorded with modern instrumentation in mainland Portugal were measured”.

Since 05:47 on Monday, nine small magnitude aftershocks have been recorded, the most recent at 00:14 and 00:30 on Tuesday, the IPMA also indicated in a statement.

“Through the online macroseismic questionnaire, the IPMA has already received more than 19,000 testimonies referring to the effects of this earthquake”, it added.

The earthquake had a maximum intensity of IV/V on the Mercalli scale, classified as moderate to strong, according to the Portuguese Institute of the Sea and Atmosphere (IPMA).

With an intensity of V, considered strong, the effects can be felt outside the home. If it occurs during the night, it can wake people up. “Liquids oscillate and some overflow,” explains the IPMA.

“Small objects in unstable equilibrium move or are knocked over. Doors oscillate, close or open. Blinds and paintings move. Clock pendulums stop or start or change their state of oscillation” when an intensity of V is recorded.

The tremor was felt in several areas of Portugal and with greater intensity in the regions of Setúbal and Lisbon.

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