Egypt, while not typically considered a seismically active region, has experienced earthquakes that have highlighted the need for improved infrastructure and disaster preparedness. This article explores the history of earthquakes in Egypt, focusing on the lessons learned from past events and the measures needed to mitigate future risks.
Historical Seismic Activity in Egypt
Before 1992, Egypt was not typically considered a seismically active region, and large earthquakes were rare occurrences. However, seismic hazard in Egypt is highest at the southern end of the Gulf of Suez, the northern Red Sea and around the Gulf of Aqaba, the location of the active plate boundaries.
One of the earliest recorded devastating earthquakes occurred on July 21, 365. A powerful earthquake off the coast of Greece caused a tsunami that devastated the city of Alexandria, Egypt. Scientists now estimate that the quake was actually two tremors in succession, the largest of which is thought to have had a magnitude of 8.0. The quake was centered near the plate boundary called the Hellenic Arc and quickly sent a wall of water across the Mediterranean Sea toward the Egyptian coast. In Alexandria, approximately 5,000 people lost their lives and 50,000 homes were destroyed. Outside the city, 45,000 people were killed. In addition, the inundation of saltwater rendered farmland useless for years to come. Evidence indicates that the area’s shoreline was permanently changed by the disaster. Slowly, but steadily, the buildings of Alexandria’s Royal Quarter were overtaken by the sea following the tsunami.
The 1992 Cairo Earthquake
The 1992 Cairo earthquake, also known as the Dahshur earthquake, occurred at 15:09 local time (13:09 UTC) on 12 October. The epicenter was in the Western Desert near Dahshur, Giza, 35 km (22 mi) south of Egypt's capital city, Cairo. The earthquake was felt throughout most of northern Egypt, in Alexandria, Port Said and as far south as Asyut, and in southern Israel.
The 5.8 magnitude earthquake struck in 1992, it highlighted the need for Egypt to improve its infrastructure and prepare for potential earthquakes. The disastrous effect of the earthquake is presented here in interactive maps as well as tables recording multiple sets of data disaggregated by governorate: damaged buildings, affected families, and deaths. Three decades on, it was surprising to find little information on it, so much so that many writings refer to it as the Cairo Earthquake, even though many other places were affected. This report maps the widespread impact of the 1992 Dahshur (Egypt) Earthquake.
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Around 40,000 of the affected buildings were in the capital, Cairo, representing over one third of all buildings. The areas of greatest damage were in the historic neighborhoods of Historic Cairo, Old Cairo and Bulaq. Damage was reported to have affected 212 out of a total of 560 historical monuments.
The earthquake led to the displacement of more than 100,000 families from destroyed or heavily damaged homes. Nearly 45 % of the homeless were in Giza - 86 % of those were village houses in rural Giza, followed by 44 % in Cairo - all urban, and 5 % in Fayoum - again almost all rural.
| Governorate | Deaths | Homeless Families | Damaged Buildings |
|---|---|---|---|
| Giza | 218 | ~45,000 | 5292 houses collapsed or were damaged beyond repair, and 12,700 needed significant repair |
| Cairo | 205 | ~44,000 | 40,000 |
| Qalubia | 58 | 859 out of 1384 families were relocated | N/A |
| Fayoum | N/A | ~5,000 | Villages in north-eastern Fayoum were also close to the epicentre |
According to the final Cabinet dispatch on the matter, published six weeks after the earthquake, a total of 561 people died and 12,392 were injured. Giza, the governorate where the earthquake’s epicenter was located, was the worst-hit with 218 deaths, followed by Cairo which witnessed 205 deaths, and Qalubia 58. Together, these three governorates hold Egypt’s and the region’s largest metropolis, Greater Cairo, which at the time was home to 10 million people.
Most of the severe damage was confined to older masonry structures and particularly those built of adobe. The exception was a modern reinforced concrete building in Heliopolis, killing 79 people. Fortunately, many of the inhabitants were outside of the building at the time of the event.
The government was criticized for not doing much to respond.
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Egypt - Illegal building crumbles
Lessons Learned and Infrastructure Improvements
After 1992, Egypt introduced new regulations that required buildings to be designed and constructed to withstand seismic activity through appropriate structural systems and seismic-resistance materials. Design codes of practice were modified to include clauses addressing seismic requirements for design and construction of infrastructure and accurate seismic maps were established to complement these design requirements. However, the effectiveness of these measures is ultimately dependent on the quality of implementation and enforcement, which, of course, vary widely in Egypt.
Vulnerability Factors
There are many factors that make a building more susceptible to damage from seismic activity. One is age; seismic loads were not considered in the design of old infrastructure. Another is location: Infrastructure in areas with high seismic activity are more likely to experience strong ground motion that can cause more damage. The next is soil type, as soft soils, like loose sand or clay, can amplify ground vibration, whereas hard soils, like bedrock, are more stable during earthquakes. Additionally, tall buildings or those with horizontal or vertical design irregularities are more susceptible. Another variable is construction material. Much of Egypt’s old infrastructure was built using more brittle materials rather than reinforced steel or concrete, which hold up better to vibration.
Current and Future Preparedness
The country needs to immediately perform seismic retrofitting of old infrastructure, particularly those adopted for residence and public services. Inspection of new buildings should also be carried out and if needed, seismic retrofitting must also be applied to these buildings.
The design and construction of new infrastructure should consider seismic resilience from the start. Some special design requirements may be needed for foundations, columns and connections between horizontal and vertical structural elements. Moreover, lateral load-resisting systems must be placed in buildings as per design requirements.
The government should develop an emergency plan that outlines how different parties may react in the event of an earthquake. An official emergency alert system must also be established in addition to an aftershock preparation plan.
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Seismic Retrofitting
Seismic retrofitting is the process of making pre-existing structures more resilient to seismic activity. This can be done by adding new elements or components that help improve a structure’s stability.
Any earthquake, regardless of its magnitude, has the potential to cause damage to infrastructure and endanger people's lives. Therefore, it is important to take any earthquake seriously and assess the potential risks and impacts.
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