Kázmér et al. (2024:33) proposed that two separate earthquakes affected Umm al-Jimal, the second occurring toward the end of the Umayyad Caliphate. They estimated a local intensity of IX for this later event. Archaeoseismological indicators for both episodes included tilted and bulged walls, U-shaped collapse features, and evidence of rotational and extensional deformation. Al-Tawalbeh et al. (2019) described similar deformation in the Barracks, including tilted and bulging walls, U-shaped collapses, twisted walls, torsion-related damage, and displaced ashlars. Although they did not associate these effects with a specific event, they suggested that they most likely resulted from the second earthquake. In both cases, the second earthquake was suspected to be one of the 749 CE Sabbatical Year Earthquakes.

Osinga in Lichtenberger and Raja (2025:194) cautions, however, that “while the AD 749 earthquake may have caused destabilization of some structures and collapse of certain features,” such as portions of the Numerianos Church, “the archaeological record reveals no significant destruction that can be conclusively and solely dated to the mid-eighth century.” This uncertainty stems largely from chronological difficulties. Osinga in Lichtenberger and Raja (2025:184,184 n. 8) explains that “early Abbasid pottery shows strong continuity with late Umayyad pottery,” and “significant, traceable changes to the pottery record do not appear until around the turn of the ninth century.” She also points out that Umm al-Jimal suffers from “a lack of coin-secured deposits or other chronologically significant finds.” Although some earlier scholars speculated that Umm al-Jimal may have been abandoned after the 749 CE Sabbatical Year Earthquakes, Osinga in Lichtenberger and Raja (2025:194) concluded that “we simply cannot characterize or date the departure of the sedentary populace from Umm al-Jimal, other than to state that it almost certainly occurred prior to the ninth century,” adding that “whether this abandonment was a slow or fast process and what the underlying causes were must remain open to discussion.”

That said, archaeoseismic evidence at Umm al-Jimal is extensive, and if the sedentary population had abandoned or largely abandoned the site by the ninth century CE, the absence of later repairs has effectively preserved traces of earlier seismic activity—likely including evidence from one of the 749 CE Sabbatical Year Earthquakes—even if that evidence cannot be dated with certainty. One of the better-dated contexts is the Roman Temple which, according to Osinga in Lichtenberger and Raja (2025:186), “was later converted into a domestic structure, known as House 49.” This building contained Byzantine and Early Islamic debris, and Osinga in Lichtenberger and Raja (2025:187) note evidence of collapsed architecture on the porch (loci 036 and 040) that “may date to the Early Islamic period.” Another somewhat well-dated location is the Numerianos Church complex, where “heavy architectural collapse is noted directly above the floors that were last used in the Umayyad period,” establishing a mid-eighth-century CE terminus post quem for the “major collapse” observed in this complex. Osinga in Lichtenberger and Raja (2025) also report possible mid-eighth-century CE archaeoseismic evidence in House 119.