Lapp et al. (1980:8–9) identified a seismic destruction horizon between Stratum II, representing early Byzantine reoccupation of the Qasr, and Stratum I, marking its later Byzantine use. At the Qasr, tumbled megaliths from the walls collapsed onto Stratum II floors, and the debris that blanketed the porches made habitation impossible until the area was leveled. The builders subsequently brought in massive fills to cover the earthquake rubble before reconstructing along the same wall lines with only minor deviations. Within the Qasr, two floors were distinguished inside several rooms and outside on the west side, reflecting successive stages of occupation.

At the nearby Square Building, comparable floors and debris accumulations were documented, though the transition between Strata II and I lacked a clear break associated with the earthquake. The pottery assemblages from Stratum II in both buildings are consistent with the fourth century CE, and coins provided the critical dating limits. A Constantine II coin dated to 335–337 CE found in a Stratum II floor east of the Square Building establishes a terminus post quem, while a Theodosius I coin dating to 393–395 CE recovered from the fill above the destruction debris at the Qasr gives a terminus ante quem. This places the earthquake between 335 and 395 CE, which suggests one of the 363 CE Cyril Quakes as a plausible candidate. Occupation resumed soon after the destruction. A coin of Arcadius dated to 383–408 CE lay on an early Stratum I floor, while a coin of Zeno dated to 476–491 CE was discovered in fill above the latest floor inside the Qasr, indicating continued habitation into the late fifth century CE.