Possible evidence of the 1755 CE transatlantic tsunami in Brazil

This work addresses the transatlantic impact of the 1755 CE Lisbon tsunami on the Brazilian coast using historical description, numerical modeling and sediment analysis. Historical documents are revisited, novel numerical modeling is provided and coupled with sedimentological data. The combination of these results attests to the potential presence of CE 1755 tsunami imprints on the Brazilian coast. Building upon the available historical records, numerical simulations of tsunami generation and transoceanic propagation are conducted to identify areas along the coast of Brazil more susceptible to be affected by the 1755 CE tsunami inundation. This procedure pinpointed areas along the northern and the northeastern coasts of Brazil as locations potentially impacted by the tsunami. The geomorphological analysis allowed the definition of locations with higher potential for the preservation of tsunami deposits and thus priorities for field investigations. The 270 km field survey performed along the coast revealed the presence of a peculiar coarse "marine" sand unit. The unit comprises two layers within a coastal aeolian sequence at Pontinhas (Pernambuco, Brazil). The grain size and foraminifera analysis allows speculation on a correlation with a high-energy marine inundation as responsible for its deposition. Detailed tsunami numerical modeling -consistent with historical data - also supports this hypothesis, showing potential inundation at the location where the peculiar deposits were found. The sedimentological analysis allows a tentative association of the deposit with the 1755 CE tsunami, despite the uncertainty on its age dating.1755 CE