ACROSS

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.