1992 Cairo earthquake
Encyclopedia
The 1992 Cairo earthquake occurred at 13:09 UTC on 12 October, with an epicenter
near Dahshur
, 35 km south of Cairo
. The earthquake
had a magnitude
of 5.8, but was unusually destructive for its size, causing 545 deaths, injuring 6512 and making 50,000 people homeless. It was the most damaging event to affect Cairo since 1847.
to the Manzala rift beneath the Nile delta
.
, Bulaq and southwards along the Nile as far as Gerza, on the west bank. 350 buildings were completely destroyed and 9,000 other severely damaged. 216 mosques and 350 schools were badly damaged and about 50,000 people made homeless. Most of the severe damage was confined to older masonry structures and particularly those built of adobe
. Liquefaction
was reported from areas near the epicenter.
The high number of deaths and injuries (545 and 6512 respectively) was partly due to the amount of panic caused by the earthquake in Cairo itself.
Damage was reported to have affected 212 out of a total of 560 historic monuments in the Cairo area. A large block fell from the Great Pyramid of Giza
.
, Port Said
and as far south as Asyut
, and in southern Israel
. The calculated focal mechanism
suggests that this event originated on a WNW-ESE or W-E trending normal fault with a small strike-slip component. The aftershock
s extended about 11 km to the southeast of the main shock epicenter, indicating unidirectional rupture propagation. The estimated fault rupture length was also 11 km. The earthquake consisted of two sub-events, the second located about 27 km SE of the first.
Epicenter
The epicenter or epicentre is the point on the Earth's surface that is directly above the hypocenter or focus, the point where an earthquake or underground explosion originates...
near Dahshur
Dahshur
Dahshur , is a royal necropolis located in the desert on the west bank of the Nile approximately 40 kilometres south of Cairo...
, 35 km south of Cairo
Cairo
Cairo , is the capital of Egypt and the largest city in the Arab world and Africa, and the 16th largest metropolitan area in the world. Nicknamed "The City of a Thousand Minarets" for its preponderance of Islamic architecture, Cairo has long been a centre of the region's political and cultural life...
. The earthquake
Earthquake
An earthquake is the result of a sudden release of energy in the Earth's crust that creates seismic waves. The seismicity, seismism or seismic activity of an area refers to the frequency, type and size of earthquakes experienced over a period of time...
had a magnitude
Body wave magnitude
Body wave magnitude is a way of determining the size of an earthquake, using the amplitude of the initial P-wave to calculate the magnitude. The P-wave is a type of body wave that is capable of traveling through the earth at a velocity of around 5 to 8 km/s, and is the first wave from an...
of 5.8, but was unusually destructive for its size, causing 545 deaths, injuring 6512 and making 50,000 people homeless. It was the most damaging event to affect Cairo since 1847.
Geology
Cairo is sited within a diffuse zone of faulting that transfers extension from the Gulf of Suez RiftGulf of Suez Rift
The Gulf of Suez Rift is a continental rift zone that was active between the Late Oligocene and the end of the Miocene . It represented a continuation of the Red Sea Rift until break-up occurred in the middle Miocene, with most of the displacement on the newly developed Red Sea spreading centre...
to the Manzala rift beneath the Nile delta
Nile Delta
The Nile Delta is the delta formed in Northern Egypt where the Nile River spreads out and drains into the Mediterranean Sea. It is one of the world's largest river deltas—from Alexandria in the west to Port Said in the east, it covers some 240 km of Mediterranean coastline—and is a rich...
.
Damage
The areas of greatest damage were in Old CairoOld Cairo
Old Cairo is a part of Cairo, Egypt, that contains the remnants of those cities which were capitals before Cairo, such as Fustat, as well as some other elements from the city's varied history. For example, it encompasses Coptic Cairo and its many old churches and ruins of Roman fortifications...
, Bulaq and southwards along the Nile as far as Gerza, on the west bank. 350 buildings were completely destroyed and 9,000 other severely damaged. 216 mosques and 350 schools were badly damaged and about 50,000 people made homeless. Most of the severe damage was confined to older masonry structures and particularly those built of adobe
Adobe
Adobe is a natural building material made from sand, clay, water, and some kind of fibrous or organic material , which the builders shape into bricks using frames and dry in the sun. Adobe buildings are similar to cob and mudbrick buildings. Adobe structures are extremely durable, and account for...
. Liquefaction
Soil liquefaction
Soil liquefaction describes a phenomenon whereby a saturated soil substantially loses strength and stiffness in response to an applied stress, usually earthquake shaking or other sudden change in stress condition, causing it to behave like a liquid....
was reported from areas near the epicenter.
The high number of deaths and injuries (545 and 6512 respectively) was partly due to the amount of panic caused by the earthquake in Cairo itself.
Damage was reported to have affected 212 out of a total of 560 historic monuments in the Cairo area. A large block fell from the Great Pyramid of Giza
Great Pyramid of Giza
The Great Pyramid of Giza is the oldest and largest of the three pyramids in the Giza Necropolis bordering what is now El Giza, Egypt. It is the oldest of the Seven Wonders of the Ancient World, and the only one to remain largely intact...
.
Earthquake characteristics
The earthquake was felt throughout most of northern Egypt, in AlexandriaAlexandria
Alexandria is the second-largest city of Egypt, with a population of 4.1 million, extending about along the coast of the Mediterranean Sea in the north central part of the country; it is also the largest city lying directly on the Mediterranean coast. It is Egypt's largest seaport, serving...
, Port Said
Port Said
Port Said is a city that lies in north east Egypt extending about 30 km along the coast of the Mediterranean Sea, north of the Suez Canal, with an approximate population of 603,787...
and as far south as Asyut
Asyut
Asyut is the capital of the modern Asyut Governorate in Egypt; the ancient city of the same name is situated nearby. The modern city is located at , while the ancient city is at .- Etymology :...
, and in southern Israel
Israel
The State of Israel is a parliamentary republic located in the Middle East, along the eastern shore of the Mediterranean Sea...
. The calculated focal mechanism
Focal mechanism
The focal mechanism of an earthquake describes the inelastic deformation in the source region that generates the seismic waves. In the case of a fault-related event it refers to the orientation of the fault plane that slipped and the slip vector and is also known as a fault-plane solution...
suggests that this event originated on a WNW-ESE or W-E trending normal fault with a small strike-slip component. The aftershock
Aftershock
An aftershock is a smaller earthquake that occurs after a previous large earthquake, in the same area of the main shock. If an aftershock is larger than the main shock, the aftershock is redesignated as the main shock and the original main shock is redesignated as a foreshock...
s extended about 11 km to the southeast of the main shock epicenter, indicating unidirectional rupture propagation. The estimated fault rupture length was also 11 km. The earthquake consisted of two sub-events, the second located about 27 km SE of the first.