Historical Seismic Events and Their Traces on Medieval Religious Buildings

The Casentino valley, located in the province of Arezzo, is home to several medieval religious complexes, notably parish churches and pieves. These structures, dating from the early Christian period, have long been the subject of archaeological and historical study. These religious sites are often situated on ancient Etruscan or Roman settlements, with their development and transformation being influenced by seismic events, which have left significant traces in the built heritage. While numerous works have investigated the architectural evolution and artistic significance of these religious buildings, a limited focus has been placed on the seismic history of the region. The research applies an interdisciplinary approach combining archaeoseismology, architectural archaeology, and 3D survey technologies to explore the seismic impact on the Casentino's religious structures. The study involved detailed laser scanning and 3D photomodeling of four key parish churches (Socana, Romena, Buiano, and Vado), with a particular focus on the Pieve of Sant’Antonio at Socana and the Pieve of Santa Maria at Buiano. Through these techniques, a comprehensive database of construction phases, wall stratigraphy, and deformation mechanisms was created. Stratigraphic analysis revealed key periods of reconstruction, particularly in the 12th-13th and 16th centuries. The study also incorporated architectural analysis to identify structural instabilities and their potential relationship to seismic events, notably the 1504 earthquake. This research significantly advances the field of archaeoseismology by integrating modern 3D survey techniques, such as laser scanning and photogrammetry, with traditional archaeological analysis. The application of historical building information modeling (HBIM) to the Pieve of Buiano’s apse exemplifies the innovation in documenting complex construction phases and plastic deformations due to seismic stress. This methodology not only uncovers previously undocumented seismic events in the Casentino, particularly in the 12th-13th and 16th centuries, but also enhances our understanding of how seismic forces affected architectural structures. By bridging the gap between historical documents and structural analysis, the study provides crucial insights into the seismic history of the Casentino valley and highlights the importance of preserving these sites for future generations. Furthermore, this approach offers a valuable model for the study and conservation of seismic heritage in similar regions.