A Chronology of Ancient Earthquake Damage in the Modena Cathedral (Italy): Integrated Dating of Mortars (¹⁴C, Pollen Record) and Bricks (TL)

ABSTRACT

The 15th century cross-vaults of the medieval Modena Cathedral (UNESCO site) consist of intricate patches of different masonry portions bound by three types of lime mortars and at least two types of gypsum mortars. Such anomalous structure suggests multiple repair works over time after damaging earthquakes.

The absolute dating of lime mortars (¹⁴C) and bricks (TL) integrated with the pollen record of mortars allowed to clarify the construction and restoration history of the vaults and to link the repairs to the earthquake chronology for the area. The results reveal that the original construction of the vaults (1404–1454) was carried out using lime mortar binding reused Roman and medieval older bricks. Lime mortar was used also for later repairs caused by earthquakes in the 16th and 17th centuries. Gypsum mortars were then used to entirely rebuild some vaults and to repair others in the 18th and 19th centuries.

The study indicates that unexpected damage could be revealed by the detailed chronology of masonry binders. These data represent fundamental steps to implement earthquake risk assessments and strengthening projects of ancient buildings.

KEYWORDS:

• Brick dating
• chronology
• earthquake damage
• gypsum mortar
• lime mortar dating
• pollen

Acknowledgments

We thank Capitolo metropolitano, Soprintendenza archeologia, belle arti e paesaggio per la città metropolitana di Bologna e le province di Modena, Reggio Emilia e Ferrara and Comune di Modena for the cooperation and support.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported financially by Capitolo metropolitano and Comune di Modena.