The IPMA indicated that it is not possible to establish a link between the earthquake measuring 3.0 on the Richter scale recorded and felt today near Sesimbra with the tremor that occurred on August 26.
An earthquake measuring 3.0 on the Richter scale was recorded at 02:26 today with its epicentre approximately 30 kilometres from Sesimbra, in the district of Setúbal, in a submerged area, without causing any personal or material damage. Previously, the Portuguese Institute of the Sea and Atmosphere (IPMA) had reported a magnitude of 3.1.
The earthquake was felt with low intensity, possibly with a maximum grade III (Modified Mercalli scale) in the municipalities of Setúbal, Sines and Sesimbra, and other locations in the district of Lisbon.
The IPMA stressed that the event is part of the “normal activity of the territory and is not indicative of an increase in seismicity in Portugal”.
“It should be noted that it is not possible to establish a relationship between this earthquake and the one that occurred on August 26th,” reads the statement released.
On that day, an earthquake measuring 5.3 on the Richter scale was recorded at 05:11, 58 kilometres west of Sines (also in the district of Setúbal), and did not cause any casualties or material damage, with aftershocks following.
This earthquake, according to the IPMA, did not cause personal or material damage and was felt with a maximum intensity of IV/V (Modified Mercalli scale) in the Sines region and with less intensity in the areas of Setúbal and Lisbon.
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 extreme (when greater than 10).
The Modified Mercalli scale measures “degrees of intensity and their description”.
With an intensity of IV, considered moderate, “suspended objects sway, the vibration is similar to that caused by the passage of heavy vehicles or the sensation of a heavy ball hitting walls, parked cars sway, windows, doors and crockery shake, glass and crockery rattle or tinkle and at the highest level of this degree, walls and wooden structures creak”, describes the institute on its website.
With an intensity III, considered weak, the tremor is felt inside the house and hanging objects sway, feeling a “vibration similar to that caused by the passage of heavy vehicles”.