Description: Proxy reconstructions of tropical Atlantic sea surface temperature (SST) that extend beyond the period of instrumental observations have primarily focused on centennial to millennial variability rather than on seasonal to multidecadal variability. Here we present monthly-resolved records of Sr/Ca (a proxy of SST) from fossil annually-banded Diploria strigosa corals from Bonaire (southern Caribbean Sea). The individual corals provide time-windows of up to 68 years length, and the total number of 295 years of record allows for assessing the natural range of seasonal to multidecadal SST variability in the western tropical Atlantic during snapshots of the mid- to late Holocene. Comparable to modern climate, the coral Sr/Ca records reveal that mid- to late Holocene SST was characterised by clear seasonal cycles, persistent quasi-biennial and prominent interannual as well as inter- to multidecadal-scale variability. However, the magnitude of SST variations on these timescales has varied over the last 6.2 ka. The coral records show increased seasonality during the mid-Holocene consistent with climatemodel simulations indicating that southern Caribbean SST seasonality is induced by insolation changes on orbital timescales,whereas internal dynamics of the climate system play an important role on shorter timescales. Interannual SST variability is linked to ocean– atmosphere interactions of Atlantic and Pacific origin. Pronounced interannual variability in the western tropical Atlantic is indicated by a 2.35 ka coral, possibly related to a strengthening of the variability of the El Niño/Southern Oscillation throughout the Holocene. Prominent inter- to multidecadal SST variability is evident in the coral records and slightly more pronounced in the mid-Holocene. We finally argue that our coral data provide a target for studying Holocene climate variability on seasonal and interannual to multidecadal timescales, when using further numerical models and high-resolution proxy data.

Description: Historical earthquake catalogs are one of the building blocks for the assessment of seismic hazard. Despite many years of research in the archives, many earthquakes remain poorly known. New sources of informationare hence required.Among these, historical buildings are witnesses of natural catastrophes recorded in their walls as structural disorders, repairs, and restorations. Our project aims to study past earthquakes using buildings as “stone seismometers”, analyzing the seismic ground motions required to explain building repairs/disorders, or their absence. The 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.An interdisciplinary connecting “ArChaeology, inventory of RecOnstruction, Seismology and Structural engineering” (ACROSS) is introduced to gain such knowledge. Based on innovative techniques to inventory repairs in the building archaeology; seismic input signals consistent with the seismotectonic context; digital building models implementing realistic geometry and construction materials as well as robust modelling of masonry behaviour, the ACROSS method is declined in five steps, 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 for seismic dynamic analysis.4. Comparison of the numerical analysis results, based on previous steps, with repairs and damage mechanisms.The method is applied to six bell towers located in the Mugello basin (Tuscany, Italy). They were affected by many historical earthquakes at least from the middle of the 16th century.