Earthquakes in Argentina

Argentina's seismic hazard is concentrated along its western edge, where the Nazca plate subducts beneath South America and builds the Andes. In the central-western provinces of San Juan and Mendoza, part of the subducting slab flattens out horizontally, a 'flat-slab' segment that pushes deformation far inland and activates a dense network of shallow crustal faults beneath populated valleys. The vast eastern lowlands, by contrast, are tectonically quiet.

The 1944 San Juan earthquake, a magnitude 7.0 shock on a nearby fault, struck the city directly and killed around 10,000 people, roughly a tenth of its population, making it the deadliest natural disaster in Argentine history. The catastrophe reshaped the country's building codes and, famously, marked the political rise of Juan Domingo Perón, who led the relief effort.