The 1755 Meknes earthquake affected

Morocco Morocco (),, ) officially the Kingdom of Morocco, is the westernmost country in the Maghreb region of North Africa. It overlooks the Mediterranean Sea to the north and the Atlantic Ocean to the west, and has land borders with Algeria to ...

on 27 November 1755. The earthquake had a moment magnitude () estimated at between 6.5 and 7.0. It devastated the cities of

Fes Fez or Fes (; ar, فاس, fās; zgh, ⴼⵉⵣⴰⵣ, fizaz; french: Fès) is a city in northern inland Morocco and the capital of the Fès-Meknès administrative region. It is the second largest city in Morocco, with a population of 1.11 mi ...

and

Meknes Meknes ( ar, مكناس, maknās, ; ber, ⴰⵎⴽⵏⴰⵙ, amknas; french: Meknès) is one of the four Imperial cities of Morocco, located in northern central Morocco and the sixth largest city by population in the kingdom. Founded in the 11th c ...

—killing at least 15,000 people in both cities.

Tectonic setting

The western

Eurasian Eurasia (, ) is the largest continental area on Earth, comprising all of Europe and Asia. Primarily in the Northern Hemisphere, Northern and Eastern Hemispheres, it spans from the British Isles and the Iberian Peninsula in the west to the Ja ...

–

Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

plate boundary Plate tectonics (from the la, label=Late Latin, tectonicus, from the grc, τεκτονικός, lit=pertaining to building) is the generally accepted scientific theory that considers the Earth's lithosphere to comprise a number of large te ...

is dominated by the Gloria Fault System which lies between the

Azores Triple Junction The Azores Triple Junction (ATJ) is a geologic triple junction where the boundaries of three tectonic plates intersect: the North American Plate, the Eurasian Plate and the African Plate. This triple junction is located along the Mid-Atlantic ...

and

Gibraltar Arc The Gibraltar Arc is a geological region corresponding to an arcuate orogen surrounding the Alboran Sea, between the Iberian Peninsula and Africa. It consists of the Betic Cordillera (south Spain), and the Rif (North Morocco). The Gibraltar Arc i ...

. The plate boundary around the Gibraltar Arc and Alboran Sea area is less defined and chacterized by a broad zone of seismicity. The African and Eurasian plates converge in a N–S to NNW–SSE direction. The convergence is related to uplift and thrust tectonics along the Rif mountains.

Earthquake

The shock came just days after

another earthquake ''Another Earthquake!'' is the fourth studio album by American teen pop singer Aaron Carter, released on September 3, 2002. The album made its chart debut at number 18 on the US ''Billboard'' 200 (with 41,000 units sold), but fell to number 41 ( ...

affected Lisbon (1 November)—it was mistakenly identified as an

aftershock In seismology, an aftershock is a smaller earthquake that follows a larger earthquake, in the same area of the main shock, caused as the displaced crust adjusts to the effects of the main shock. Large earthquakes can have hundreds to thousand ...

of that event, and misdated to 18 November. Arab sources attribute the earthquake to 27 November and mezoseismal area to Fes and Meknes. A seismic rupture was also reported but poorly documented. During a field survey of the area in 2017,

surface rupture In seismology, surface rupture (or ground rupture, or ground displacement) is the visible offset of the ground surface when an earthquake rupture along a fault affects the Earth's surface. Surface rupture is opposed by buried rupture, where the ...

s were identified along the -long Southern Rif front; a

thrust fault A thrust fault is a break in the Earth's crust, across which older rocks are pushed above younger rocks. Thrust geometry and nomenclature Reverse faults A thrust fault is a type of reverse fault that has a dip of 45 degrees or less. If ...

with some left-lateral strike-slip component. The fault displays a listric geometry and is connected with a

décollement Décollement () is a gliding plane between two rock masses, also known as a basal detachment fault. Décollements are a deformational structure, resulting in independent styles of deformation in the rocks above and below the fault. They are ass ...

at its base; dipping at 60° near the surface to 35° at depth. A slip rate was estimated at /yr for the

Holocene The Holocene ( ) is the current geological epoch. It began approximately 11,650 cal years Before Present (), after the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene togethe ...

. The fault accommodates convergence between the

African Plate The African Plate is a major tectonic plate that includes much of the continent of Africa (except for its easternmost part) and the adjacent oceanic crust to the west and south. It is bounded by the North American Plate and South American Plat ...

and the

Rif The Rif or Riff (, ), also called Rif Mountains, is a geographic region in northern Morocco. This mountainous and fertile area is bordered by Cape Spartel and Tangier to the west, by Berkane and the Moulouya River to the east, by the Mediterrane ...

. The last earthquake along the fault produced of coseismic slip—by assuming that as the average slip across a surface rupture, the moment magnitude obtained was 6.5–7.0. Although not considered an aftershock of the 1 November Lisbon earthquake, it may have been an example of a

triggered earthquake Remotely triggered earthquakes are a result of the effects of large earthquakes at considerable distance, outside of the immediate aftershock zone. The farther one gets from the initiating earthquake in both space and time, the more difficult it i ...

due to stress transfer.

Damage

The earthquake caused great devastation in Fes and Meknes; tens of thousands were killed. It was followed by strong aftershocks that continued for months. At Meknes, only a few homes remained standing but were badly damaged. Of the 16,000 Jews in the city, only 8,000 survived—an additional 4,000 Muslims perished. In Fez, 3,000 people died. Significant damage occurred at the Roman archeological site

Volubilis Volubilis (; ar, وليلي, walīlī; ber, ⵡⵍⵉⵍⵉ, wlili) is a partly excavated Berber-Roman city in Morocco situated near the city of Meknes, and may have been the capital of the kingdom of Mauretania, at least from the time of Kin ...

. Several kilometers south of Volubilis,

Moulay Idriss Zerhoun Moulay Idriss, Moulay Driss Zerhoun or simply Zerhoun ( ar, مولاي إدريس زرهون) is a town in the Fès-Meknès region of northern Morocco, spread over two hills at the base of Mount Zerhoun. It is famous for being the site of the tomb ...

was badly affected by a major landslide. The documentation of surface ruptured led geologists to conclude the event was localized and this was a local earthquake. Surface ruptures associated with an E–W fault at Jebel Zerhoun and Jebel Zalagh, north of Fes and Meknes were studied.

Tectonic setting

Earthquake

Damage

See also

References

Further reading