A drag fold is a small-scale fold that forms adjacent to a fault, where the movement along the fault causes the rock layers to bend. Drag folds are typically asymmetrical and provide valuable insights into the direction and sense of fault movement. They are important structures in structural geology for interpreting the kinematics of fault zones.
Reference: Ramsay, J. G., & Huber, M. I. (1987). “The Techniques of Modern Structural Geology, Volume 2: Folds and Fractures.” Academic Press.