Definition of a strategy to characterize historical ground motion based on ArChaeology, inventory of RecOnstruction, Seismology and Structural engineering – ACROSS

The ACROSS method is declined in five steps, each of them challenging the concerned disciplines to use methods and technics at the state of the art and to strongly interact among them to obtain reliable outcomes, useful for all the involved communities.

Collecting the data produced by the archaeology of the buildings and the study of historical sources.

Identification of damage mechanisms.

Definition of the digital building model used to perform seismic dynamic analysis.

Definition of ground motions to be used as input for the building dynamic analysis.

Comparison of the results of the numerical analysis, based on previous steps, with repairs and damage mechanisms.

If the observed damages are successfully reproduced, then it is possible to retrieve quantitative information on the past ground motion features by analogy with the ones used in the dynamic analysis.

ACROSS is focused on a test site offering challenges, attractiveness and opportunities to all the involved specialists: the Mugello basin in central Apennines (Italy), an exceptional site under many points of view. The region boasts homogeneity of historical archives over seven centuries (1200-1900). Its valuable cultural heritage is characterized by medieval buildings, that have been restored and preserved through the centuries. Geologically, Mugello is an intramontane basin bordered by two large antithetic normal fault systems.

The work based on a single test site is not sufficient to constrain the source of the earthquakes, neither the impact of the alluvial basin properties on the ground motion. For this reason, in ACROSS, we propose to extent this approach to five bell towers disseminated in and around the Mugello basin.

Each step of the ACROSS project will lead to a milestone.

First result expected from ACROSS method: a timeline tracing building phases, repairs, earthquakes occurrence, and a quality factor expressing the causal link between repairs and ground shaking. This output is built on the interaction between archaeologists, petrologists, historians and civil engineers. The challenge is to create a quantitative data set describing the evolution of the building vulnerability along the centuries.

A second major result of ACROSS method is the definition of a realistic masonry building model, to be used to study the dynamic response under seismic loading. The scientific barriers to be lifted are to assess building vulnerability through its damage/repairs history and to introduce advanced modelling strategies for unreinforced masonry.

The third major result of ACROSS project is the selection/generation of input ground motions representative of historical earthquakes. The challenge is to obtain realistic physics-based strong ground motions, reflecting the local geology properties and usable as input for dynamic response analysis of the building.

The main result expected from ACROSS method is the relation between the observed damage and the ground shaking. The scientific barriers to be lifted are to optimize the time computation for dynamic analysis and to establish damage model able to describe failure mechanisms observed for the building.

ACROSS method is a nexus in which the disciplines collect high-quality data, implement methods at state of the art, and share knowledge to achieve a common goal: delivering a quantitative description of the ground motion induced by past earthquakes. The method and its scope are far beyond the state of the art in studying past earthquakes. The contribution of the consortium partners to the state of the art, along with the results achieved in the framework of the ongoing work in Mugello area, demonstrate the capability of the involved researchers to rise to the challenge.


If the Mugello basin is an ideal test case for the development and validation of the ACROSS methodology, the project perspective is to extend and adapt the proposed approach to other test cases with different degrees of knowledge (archaeological, historical, geological) like France mainland or other EU countries.

To be followed....

Historical earthquake catalogues are one of the building blocks for the evaluation of seismic hazard. In spite of many years of research in archives, many earthquakes remain poorly known. New sources of information are hence required. Historical buildings are witnesses of natural catastrophes recorded in their walls as structural disorders or repairs. The ambition of this project is to study past earthquakes using buildings as “stone seismometers”, analysing the seismic ground motions necessary to explain building repairs/disorders, or their absence. To gain such a knowledge, it is necessary to define an interdisciplinary strategy based on: innovative techniques introduced in the building archaeology; seismic input signals consistent with the seismotectonic context; digital building models based on realistic geometry and construction materials. With this aim, a methodology connecting “ArChaeology, inventory of RecOnstruction, Seismology and Structural engineering” ACROSS is introduced.
The project goal is to demonstrate that archaeological characterization of post-seismic repairs on buildings can be successfully used to infer key ground motion and earthquake source characteristics of historical earthquakes.
The ACROSS method is declined in five steps, each of them challenging the concerned disciplines to use methods and technics at the state of the art and to strongly interact among them to obtain reliable outcomes, useful for all the involved communities.
1. Collecting the data produced by the archaeology of the buildings and the study of historical sources.
2. Identification of damage mechanisms
3. Definition of the digital building model used to perform seismic dynamic analysis.
4. Definition of ground motions to be used as input for the building dynamic analysis.
5. Comparison of the results of the numerical analysis, based on steps 3 and 4, with repairs and damage mechanisms, identified in steps 1 and 2.
If the observed damages are successfully reproduced, then it is possible to retrieve quantitative information on the past ground motion features by analogy with the ones used in the dynamic analysis.
The ambition of ACROSS is to move from catalogues of historical seismicity to the definition of the historical ground motion at a given site.