Marrakesh is the largest city affected by the current earthquake. Since 1900, there have been 9 earthquakes of magnitude 5 or higher within 500 km of the location of the current earthquake, but none of them were magnitude 6 or higher. As you remember, the difference between each rank and the one above it is 10 times stronger
An earthquake with a magnitude of 6.8 occurred on Friday night, September 8, 2023, near Okaymden in Morocco. This devastating earthquake left more than 1,000 dead and about that number injured. This estimate is a missing estimate because many of the residents near the head center live in inaccessible settlements, many in the mountains in mud and mud houses. The earthquake was also felt in nearby Marrakesh and caused significant damage in the area.
According to the US Geological Survey, the cause of the strong earthquake was an inverted oblique shock at a shallow depth within the High Atlas Mountains of Morocco, about 75 km southeast of Marrakesh.
The High Atlas Mountains contain a variety of mapped strike-slip and thrust replicas, trending east-west and northeast-southwest. This earthquake occurred within the African plate, about 550 km south of the plate boundary between the African plate and the Eurasian plate. At the location of this earthquake, the African plate is moving about 24 mm/yr WSW relative to the Eurasian plate.
While earthquakes are usually depicted as dots on maps, earthquakes of this magnitude are more appropriately depicted as sliding over a larger aftershock area. Reverse replica events on the scale of the September 8, 2023 Morocco earthquake are typically 30 by 20 km in size.
Earthquakes of this magnitude in the region are rare but not unexpected. Since 1900, there have been 9 earthquakes of magnitude 5 or higher within 500 km of the location of the current earthquake. None of them were above power 6.
This seismic event was extremely unusual for Morocco but especially for the southwest of the country, an area that has not known such strong earthquakes. Moreover, even within a radius of 500 kilometers from the epicenter, an earthquake of such intensity has not occurred since the 19th century. This lack of familiarity has consequences. The population's memory of the earthquake will be limited and so will preparedness.
If these earthquakes occur at night the death toll increases because people tend to be inside buildings and many of them may collapse on them.
The US Geological Survey operates a model that estimates the extent of casualties and probable economic losses. This indicates that the number of dead could reach several thousand. However, the aftershocks must also be taken into account, even if their intensity is a little lower (that is, only about a tenth of the intensity) they may collapse buildings that have already been damaged.
As of September 9, 2023, rescue and recovery efforts are ongoing, and the situation is being continuously monitored. This event highlights the importance of disaster preparedness and response in areas historically not known for seismic activity.
More of the topic in Hayadan: