In the early morning of what was probably the 13th of December in 115 CE, Antioch was struck by a powerful earthquake, the 115 CE Trajan Quake, which caused widespread building collapses and heavy loss of life. The disaster is well documented, likely in part because Roman Emperor Trajan was in Antioch at the time, using the city as his base for campaigns against the Parthian Empire. The date is provided by Antiochene chronicler Johannes Malalas, writing in the 6th century CE, who may have drawn on the Antioch City Chronicles.

The fullest account comes from Roman senator and historian Dio Cassius (c. 165–c. 235). Although writing a century later, his narrative is so vivid and evocative of direct observation that it strongly suggests he had access to an eyewitness account. Dio emphasized that while many cities were affected, “Antioch was the most unfortunate of all.” He describes a sudden “great bellowing roar” followed by a “tremendous quaking.” The ground was upheaved, buildings “leaped into the air,” some collapsing in pieces, others tossed about “as if by the surge of the sea.” The noise of “grinding and breaking timbers together with tiles and stones” was frightful, and the dust so thick, that “it was impossible for one to see anything or to speak or hear a word.” Even trees were uprooted and “leaped into the air, roots and all.” Wreckage spread far into the surrounding countryside.

Dio also notes rockfalls, probable landslides, and disruption of hydrology: streams disappeared while new springs burst forth. Mount Casius “was so shaken that its peaks seemed to lean over and break off and to be falling upon the very city,” while other hills also subsided ("settled"). Many inhabitants died, trapped under the rubble of their homes, and many others were injured, even those who were outside of their homes at the time that the earthquake struck. Among the dead was Pedo, the consul. Trajan was rescued through a window with only minor injuries, but aftershocks forced him to live outdoors at the hippodrome. Dio states that the aftershocks continued “for several days and nights.”

A number of other writers mentioned this earthquake including Eusebius in Chronicon, Orosius, Evagrius Scholasticus, Pseudo‑Dionysius of Tell-Mahre, George Syncellus, and Michael the Syrian.

Jordan Pickett in De Giorgi et al. (2024:438–440) discusses several possible signs of archaeoseismic activity linked to this earthquake. Among them are the destruction of Bath C and the House of Trajan’s Aqueduct, along with damage that required repairs to Trajan’s aqueduct, the colonnaded street, and the Temple of Zeus Soter. Malalas notes reconstruction projects undertaken by Trajan, though it is not always clear which works were responses to seismic damage and which were part of broader urban renewal.