Which instrument type is NOT suitable for measuring differential movement across a landslide slip surface?

An inclinometer is designed primarily to measure changes in the angle of slope or tilt, which can provide valuable information about the general movement or stability of a slope. However, when it comes to measuring differential movement across a slip surface specifically, its capability is limited. This is because an inclinometer measures angular changes rather than the specific horizontal or vertical displacements that occur along a defined slip surface.

In contrast, instruments like linear variable differential transformers, load cells, and extensometers are specifically designed to measure precise displacements or movements. Linear variable differential transformers can capture small changes in position over time, load cells can measure the change in weight or force, and extensometers are adept at measuring the stretching or compression along a defined line. Thus, the inclinometer’s focus on overall slope angle rather than the nuances of differential movement makes it unsuitable for this particular measurement task.