A palace built by the late Roman emperor Galerius near the village of Gamzigrad in Serbia is one of the most spectacular archaeological sites in the Balkans and is listed as a UNESCO World Heritage site. Archaeological surveys of the palace and its surroundings have unearthed numerous structures with severely deformed foundations. The damage to the foundations occurred in a large walled area north of the palace during a short time span at the end of the 3rd c. CE; in a second event in the middle of the 4th c. CE, an upscale villa located between the palace and the northern complex, was destroyed. An anthropogenic cause of the inclined foundations and destroyed structures could be excluded, leaving natural causes as the only explanation. The foundation inclinations show a strong correlation with the natural terrain slope, and we discuss the possibility of slope instability caused by heavy rain events or triggered by earthquake ground motions. The former seems a plausible cause of the damage to the villa due to gully erosion. Seismic ground motions predicted for the site by the European Hazard model are strong enough to trigger soil slumps of the alluvial fan on which the palace and its surroundings were built. Active faults in the vicinity are capable of producing such shaking, and nine historical earthquakes indicate that an unknown event with sufficient strength might have occurred in the 3rd c. CE.
Hinzen et al. (Tue,) studied this question.