Sciency Thoughts: Cape St. Vincent Ridge

Showing posts with label Cape St. Vincent Ridge. Show all posts

Monday, 26 August 2024

Magnitude 5.4 Eearthquake off the coast of Portugal.

The Centre Seismologique Euro-Méditeranéen recorded a Magnitude 5.4 Earthquake at a depth of 16 km off the west coast of Portugal, about 68 km to the west of the town of Sines, slightly after 5.10 am local time (slightly after 4.10 am GMT) on Monday 26 August 2024. There are no reports of any damage or casualties associated with this event, though it was felt across the Madeira Islands group, as well as in parts of the Canary Islands.

The approximate location of the 26 August 2024 Earthquake. USGS.

The Earthquake occurred close to the Cape St. Vincent Ridge, which runs along the boundary between the African and European plates to the east of the Mid-Atlantic Ridge. This is currently an area of expansion, with the two plates moving apart along this part of the boundary and new seafloor being created by the upwelling of magma from the mantle and its extrusion as a new area of crustal material, the Azores Microplate. This is not a smooth process, and can lead to occasional Earthquakes.

The location of the Cape St. Vincent Ridge relative to the Mid-Atlantic Ridge. Martins et al. 2008.

Witness accounts of Earthquakes can help geologists to understand these events, and the structures that cause them. If you felt this event you can report it to the Centre Seismologique Euro-Méditeranéen here.

Sunday, 8 March 2020

Magnitude 5.2 Earthquake to the southeast of Madeira.

The Centre Seismologique Euro-Méditeranéen recorded a Magnitude 5.2 Earthquake at a depth of 10 km to the southeast of Madeira Island, Portugal, slightly before 9.00 pm local time (GMT) on Friday 7 March 2020. There are no reports of any damage or casualties associated with this event, though it was felt across the Madeira Islands group, as well as in parts of the Canary Islands.

The approximate location of the 7 March 2020 Madeira Earthquake. USGS.

Madeira lies to the south of the Cape St. Vincent Ridge, which runs along the boundary between the African and European plates to the east of the Mid-Atlantic Ridge. This is currently an area of expansion, with the two plates moving apart along this part of the boundary and new seafloor being created by the upwelling of magma from the mantle and its extrusion as a new area of crustal material, the Azores Microplate. This is not a smooth process, and can lead to occasional Earthquakes.

Witness accounts of Earthquakes can help geologists to understand these events, and the structures that cause them. The international non-profit organisation Earthquake Report is interested in hearing from people who may have felt this event; if you felt this quake then you can report it to Earthquake Report here.

Monday, 12 May 2014

Magnitude 4.2 Earthquake on the Cape St. Vincent Ridge, west of Portugal.

The United States Geological Survey has reported a Magnitude 4.2 Earthquake at a depth of 15 km on the Cape St. Vincent Ridge, about 300 km to the west of the coast of southern Portugal, slightly after 1.45 pm GMT on Sunday 11 May 2014. While this is a moderately large quake it occurred a long way offshore in an area where it was unlikely to cause a tsunami, so there is no danger from this event, and it is highly unlikely that it was felt by anyone.

The approximate location of the 11 May 2014 Cape St. Vincent Earthquake. Google Maps.

The Cape St. Vincent Ridge runs along the boundary between the African and European plates to the east of the Mid-Atlantic Ridge. This is currently an area of expansion, with the two plates moving apart along this part of the boundary and new seafloor being created by the upwelling of magma from the mantle and its extrusion as a new area of crustal material, the Azores Microplate. This is not a smooth process, and can lead to occasional Earthquakes.