A fault that has slipped during the present seismotectonic regime and is therefore likely to have renewed displacement in the future.

A fault that is considered likely to undergo renewed movement within a period of concern to humans. Faults are commonly considered to be active if they have moved one or more times in the last 10,000 years, but they may also be considered active when assessing the hazard for very critical installations such as nuclear power plants even if movement has occurred in the last 500,000 years. Although faults that move in earthquakes today are active, not all active faults generate earthquakes - some are capable of moving aseismically (see creep, silent earthquake, slow earthquake; also, e.g., Johnston and Linde, 2002). More precise attempts (usually unsatisfactory) have been made to define “active” faults for legal or regulatory purposes.

Active fault