• from ChatGPT 5.5, 31 July 2026
• sources: Wikipedia – Damietta

Damietta (Arabic: دمياط; Dumyāṭ) is a historic port city in northern Egypt situated near the Mediterranean coast at the eastern mouth of the Nile Delta, where the Damietta branch of the Nile enters the sea. Its strategic position at the interface between the Nile River and the Mediterranean made it one of Egypt's most important commercial, naval, and defensive centers throughout history.

The city has been continuously occupied since antiquity and was known to the ancient Egyptians, Greeks, Romans, Byzantines, and later Islamic states. During the Roman and Byzantine periods it served as an important regional port, while under the Umayyads, Abbasids, Fatimids, Ayyubids, and Mamluks it became a major center for Mediterranean trade linking Egypt with the Levant, Anatolia, and Europe. Damietta was also famous for its textiles and remained one of Egypt's principal ports for centuries.

Because of its strategic importance, Damietta was repeatedly attacked during the Crusades. It was captured by Crusader forces during the Fifth Crusade in 1219 and again during the Seventh Crusade in 1249 before being retaken by the Ayyubids and later the Mamluks. Following these invasions, the medieval city was rebuilt slightly away from its earlier location to improve its defenses against future attacks.

Based on the contemporaneous account of Myrinaei Historiarum by Agathias which described seismic shaking in the Nile Delta during to the 551 CE Beirut Quake, Ambraseys (2009) suggested that there might be archeoseismic evidence for the 551 CE Beirut Quake at Damietta. Although Damietta was far from the epicenter, the possibility of seismic amplification due to a site effect in certain parts of Damietta is likely. A simple google search for "subsidence in Damietta" reveals numerous reports of modern subsidence which speaks to weak underlying sediments.

Discussion

Effect	Location	Image(s)	Description
Distorted Walls Some damage	Damietta		"Then we returned to Misr [i.e. Egypt] on the night of the 21st of Tuba, the night on which our Lady, the Virgin Mary, went to her rest. And that night there came great wrath from God, for there was a great earthquake in the land, and many houses were ruined in all the cities, and none was saved from them, not a single soul, and likewise on the sea many ships were sunk on that night. This happened all over the East, from the city of Gaza to the furthest extremity of Persia. And they counted the cities that were wrecked that night, and they were six hundred cities and villages, with a vast destruction of men and beasts. But the land of Egypt was uninjured, except only Damietta. And at Misr there was only great fear, without any death or ruin of houses; for though the beams in the doorways and walls were moved out of their places, they went back again to their places after two hours. We were assured by one whose word we trust that none of the churches of the Orthodox nor of their dwellings was destroyed throughout the east." – Severus Ibn al‑Muqaffaʿ

• Earthquake Archeological Effects chart
  Earthquake Archeological Effects (EAE)
  
  click on image to open a higher resolution version in a new tab
  
  Rodríguez-Pascua et al (2013: 221-224)
  of Rodríguez-Pascua et al (2013: 221-224)

Effect	Location	Image(s)	Description	Intensity
Displaced or Folded Walls Some damage	Damietta		"Then we returned to Misr [i.e. Egypt] on the night of the 21st of Tuba, the night on which our Lady, the Virgin Mary, went to her rest. And that night there came great wrath from God, for there was a great earthquake in the land, and many houses were ruined in all the cities, and none was saved from them, not a single soul, and likewise on the sea many ships were sunk on that night. This happened all over the East, from the city of Gaza to the furthest extremity of Persia. And they counted the cities that were wrecked that night, and they were six hundred cities and villages, with a vast destruction of men and beasts. But the land of Egypt was uninjured, except only Damietta. And at Misr there was only great fear, without any death or ruin of houses; for though the beams in the doorways and walls were moved out of their places, they went back again to their places after two hours. We were assured by one whose word we trust that none of the churches of the Orthodox nor of their dwellings was destroyed throughout the east." – Severus Ibn al‑Muqaffaʿ	VII+ ?

This evidence requires a minimum Intensity of VII (7) according to the Earthquake Archaeological Effects (EAE) classification of Rodríguez-Pascua et al. (2013:221–224). However, because Damietta lies only 1–2 m above sea level on the unconsolidated sediments of the Nile Delta, local site effects such as liquefaction and sediment amplification are expected to have increased the severity of ground failure. Consequently, the estimated bedrock intensity is reduced to VI (6).