Ostrasz and Kehrberg-Ostrasz (2020: 142) report that the Hippodrome was “already quarried for stone” by the end of the 4th century CE, and that “a number of its seat stones” were used to repair a section of the city wall, which, according to an inscription, “took place in 390 CE (Zayadine 1981a:346).” Ostrasz and Kehrberg-Ostrasz (2020: 315) also note that potters and other craftsmen had taken over the Hippodrome beginning in the late 3rd century CE. Ostrasz and Kehrberg-Ostrasz (2020: 142) propose that an earthquake may have damaged the structure so severely that it could no longer serve its racing function. They write, “It is clear that the SW part of the cavea had collapsed at a certain date and that once this happened no races could be held.” This event, they continue, “would best explain the reoccupation of and quarrying for stone in the Hippodrome.” Although “there is no direct evidence for dating the collapse of that part of the cavea,” they found it “tempting to associate it with the earthquake of 363.” Ostrasz and Kehrberg-Ostrasz (2020: 60) observed that the upper portions of the Hippodrome were the most affected—“either dismantled or partly destroyed” by an earthquake. This conclusion is supported by evidence that “stones belonging to the upper parts of the building [were] used in the passageway of the gate in the period of the intrusive occupancy” and by “the presence of architrave pieces in chamber E2” (Ostrasz and Kehrberg-Ostrasz 2020: 36).

Ostrasz and Kehrberg-Ostrasz (2020: 150) also considered the possibility that foundation problems led to “the disintegration of a large part of its masonry and of the arena.” Issues of foundation stability, including estimates of foundation pressures, are discussed in Ostrasz and Kehrberg-Ostrasz (2020:157). An east–west cross section of part of the Hippodrome (Fig. 19 below) illustrates these potential foundation instabilities, where an uncompacted fill of variable thickness lies beneath much of the structure—conditions that could easily have produced differential settlement.

Figure 19 - Schematic cross-section of hippodrome (A.O.1992) - JW: Note varying thickness of uncompacted fill which would likely to lead to differential settlement - Click on image to open in a new tab - Ostrasz and Kehrberg-Ostrasz (2020)

Although foundation instability appears to have been a factor, this does not rule out the possibility that seismic damage also contributed to the abandonment of the Hippodrome as a racing venue. Since Ostrasz and Kehrberg-Ostrasz (2020) were unaware of the mid-3rd-century CE Capitolias Theater Quake, their observation that potters and other craftsmen occupied the structure by the end of the 3rd century CE (Ostrasz and Kehrberg-Ostrasz 2020:315) suggests the possibility that the Hippodrome suffered earthquake damage sometime during the 3rd century.