The El Tigre Fault is a north-south right-lateral strike-slip fault in the province of San Juan, western Argentina, running for about 120 kilometres along the eastern edge of the Andean Precordillera. It is one of the few clearly expressed strike-slip faults in a region dominated by thrust tectonics.
The fault accommodates a component of the oblique shortening produced by the flat subduction of the Nazca Plate beneath Argentina, sliding at an estimated rate of around 1 millimetre per year. Its trace is remarkably straight and marked by offset stream channels, small pull-apart basins and pressure ridges crossing the arid Andean foothills.
Palaeoseismic trenching along the El Tigre Fault has revealed evidence of repeated surface-rupturing earthquakes in the past few thousand years, indicating it can produce events of magnitude 7 or greater. It contributes to the elevated seismic hazard of the San Juan region, one of the most earthquake-prone parts of Argentina.