When rock strata are strained beyond their ability to remain an intact unit, displacement occurs in a process known as?

The correct answer is faulting.

A fault in geology refers to discontinuity in a volume of rocks or a planar fracture, through which there exhibit a substantial displacement as an outcome of rock-mass movement.

The large faults inside the Earth's crust are the outcomes due to the activity of plate tectonic forces, with the biggest producing the boundaries between the plates, like transform faults or subduction faults. The energy related to the brisk movement on active faults is the reason for the majority of earthquakes.