A series of closely related Byzantine Greek and Latin chronicles, including Paul the Deacon, Anastasius Bibliothecarius, Theophanes, Nikephoros I of Constantinople, Georgius Monachus, George Cedrenus, and Michael Glycas, describe a destructive earthquake in Syria accompanied by ground deformation in Mesopotamia (aka Jazira).

Although the chroniclers differ in wording and detail, they agree on several distinctive geological phenomena. The ground in Mesopotamia reportedly split open to form an extensive earth fissure, estimated at approximately 2,000 feet by Paul the Deacon, Anastasius Bibliothecarius, Theophanes, and George Cedrenus, whereas Georgius Monachus increases the reported length to 3,000 feet. Several authors also describe white sandy material being ejected from the fissure. This description is consistent with liquefaction and sand boils produced by earthquake-induced expulsion of water-saturated sediment. Such observations are among the most geologically credible elements of the tradition and suggest strong ground shaking in unconsolidated deposits.

Most versions of the account then describe an event in which a white mule, or in one account an onager, emerged from the earth fissure and spoke prophecy in a human voice. Talking animals, divinely inspired prophecies, and other miraculous portents are not uncommon in Byzantine historiography, where earthquakes were frequently interpreted as manifestations of divine judgment. While the animal itself is best regarded as a literary or theological embellishment, its prophecy may preserve a genuine chronological clue. In most versions the animal foretells that a people from the desert or a foreign nation would overthrow the Arabs, a prediction the chroniclers state was subsequently fulfilled.

If this prophecy refers to the Abbasid Revolution, it would allude to the overthrow of the Arab Umayyad Caliphate by the Abbasids, a multi-ethnic movement whose military strength was drawn largely from Khurasan in the east. Although the Abbasid campaign began earlier, the decisive defeat of Marwan II at the Battle of the Zab occurred on 25 January 750 CE, after which organized Umayyad rule collapsed and the conquest of Syria rapidly followed. If the prophecy indeed reflects this historical event, it provides a terminus post quem shortly after 25 January 750 CE for this January 749 CE earthquake, suggesting that the prophetic episode was either added to, or reshaped within, the narrative after the Abbasid victory. Whether this prophetic tradition originated soon after the earthquake or was incorporated by later chroniclers cannot be determined with certainty.

The reported ejection of white sandy material from the earth fissures is consistent with liquefaction and the formation of sand boils during strong ground shaking. Using a chart (Fig. 9) from Obermeier (1996), the observed liquefaction suggests Peak Horizontal Ground Acceleration (PGA) values of approximately 0.2–0.5 g, corresponding to Intensity (I) = 6.7–8.2 using the transform of Wald et al. (1999). This is consistent with the minimum intensity of VII assigned to liquefaction and sand injection features by the Earthquake Archaeological Effects scale of Rodríguez-Pascua et al. (2013).