Differential earthquake footprints on the masonry styles at Qal’at al-Subayba (Nimrod fortress) support the theory of its ancient origin

Abstract

Qal’at al-Subayba (Nimrod Fortress), one of the largest medieval fortresses in the Middle East, is strategically located above the city of Banias on the ancient highway from Tyre to Damascus. Scholars have attributed the founding of the fortress to different rulers and periods. Current theory attributes the fortress founding to the Ayyubids. Although the Ayyubic theory is widely accepted, it relies primarily upon alternative interpretation of historical sources rather than firsthand observations. The fortress was constructed using distinctively different masonry styles. The primary styles, Massive, Crusader, Ayyubic, and Mamluk, are characterized here. Some of these masonries carry earthquake footprints and findings show that the damage is correlated with the specific masonry rather than geographical or other constraints. The Massive masonry sustained the greatest damage. The Crusader masonry was damaged to a lesser extent and the Ayyubic and Mamluk were spared. Based on these findings, it is concluded that the fortress was hit by two powerful earthquakes, the one of A.D 749 and the one of A.D 1202. The earthquake of A.D 749 devastated the Massive masonry, prior to later constructions. As this masonry has Hellenistic characteristics, it is suggested that the fortress was founded by the Greco-Syrians.