Furthermore, a gravitational memory effect, named displacement memory effect, can be associated with a BMS supertranslation. When a gravitating radiation pulse transit past arrays of detectors stationed near future null infinity in the vacuum, the relative positions and clock times of the detectors before and after the radiation transit differ by a BMS supertranslation. The relative spatial displacement found for a pair of nearby detectors reproduces the well-known and potentially measurable gravitational memory effect. Hence the displacement memory effect both physically manifests and directly measures the action of a BMS supertranslation.