The quake, which was registered at 2.03am and went largely unnoticed, is officially classified as ‘small’.
This comes as four researchers from Évora university concluded that Lisbon and the Algarve are the two regions in Portugal most at risk of experiencing earthquakes.
The researchers reached this conclusion after mapping analyses of 175 quakes registered in Portugal over more than 700 years.
The study was published in scientific magazine ‘Seismological Research Letters’ and included the first ever map of Portugal highlighting critical seismic risk zones.
Portugal has suffered several devastating earthquakes in the past, the largest being the 1755 quake that demolished most of Lisbon and was felt throughout Europe.