What is an editing technique in which a cut creates a gap in the sequence that is jarring to the viewer?

The editing technique referred to in the question is known as a jump cut. A jump cut occurs when a continuous shot is interrupted by cutting to another shot that is taken from a different position or has a significant change in time. This abrupt transition creates a noticeable gap in the sequence, which can be jarring to the viewer. Jump cuts are often used in filmmaking to convey a sense of urgency or to emphasize a particular moment, but they can also be unsettling if overused or misused, as they disrupt the smooth flow of the narrative.

Other editing techniques such as crossfades, fade-outs, and transitions generally serve to smooth out or blend together scenes, creating a more seamless viewing experience. Crossfades gradually blend two shots, fade-outs transition a scene to black, and transitions encompass a wide range of effects designed to connect shots without the abruptness that characterizes a jump cut.