Digital Survey and Structural Investigation on the Triumphal Arch of Caracalla in the Archaeological Site of Volubilis in Morocco: Retracing the Timeline of Collapses Occurred during the 18th Century Earthquake

A low seismic acceleration of just 0.168 g was sufficient to cause the collapse of the Triumphal Arch of Caracalla at Volubilis, Morocco, during the 1755 Lisbon earthquake—a finding that aligns with current Moroccan seismic codes estimating a demand of 0.16 g for the region. This discovery underscores the arch's vulnerability, as its capacity matches the expected seismic demand, leaving it inadequately protected against unexpected events. The study retraced the timeline of collapses using digital surveys and structural analyses, including rigid-block and continuous finite element (FE) models, based on historical investigations and data collected in 2017. These methods revealed that the visible arch today is a reconstruction from 1930, masking its original state after the 18th-century earthquake.

Galassi, S., Bigongiari, M., Tempesta, G., Rovero, L., Fazzi, E., Azil, C., Di Pasquale, L., & Pancani, G. (2022). Digital Survey and Structural Investigation on the Triumphal Arch of Caracalla in the Archaeological Site of Volubilis in Morocco: Retracing the Timeline of Collapses Occurred during the 18^th Century Earthquake. International Journal of Architectural Heritage, 16(6), 940–955. https://doi.org/10.1080/15583058.2022.2045387