Kanellopoulos (2001:16) speculated that a partial collapse of the upper story of Room 28 along the Colonnaded Street was caused by the southern 363 CE Cyril Quake. Expanding this interpretation, Fiema (2008) argued that damage in the Colonnaded Street area likely included “shifted walls, collapsed columns and arches, and a damaged pavement.” He further observed that the street “appears to have been only partially rebuilt after the earthquake,” noting that later structures were erected on the sidewalk using reused architectural elements, including column drums and inscribed blocks. According to Fiema, the reuse of these drums indicates that parts of the original colonnade collapsed during the earthquake and were never restored, pointing to a long-term reduction in the monumental character of the street following seismic damage.

Earlier excavation evidence supports this interpretation. Fiema (1998:398) discussed archaeoseismic indicators from previous work in the area, where excavation of a shop along the Colonnaded Street revealed a clear destruction horizon. The shop excavated by Parr was abandoned following what Russell (1980) identified as the disastrous earthquake of 19 May 363 CE, preserving a distinct layer of destruction debris (Phase XV) that marks a sudden interruption of use rather than gradual decline ( Parr 1970: 366–368).