TDR senses ground movement through distortion to a coaxial cable induced by the ground movement.The signal can be affected by the nature of the material surrounding the TDR cable.

• TDR利用电磁脉冲于同轴电缆中行进时，碰到截面变化而反射量测地层滑动，但同轴缆线之变形受到外部束制材料的影响而有所不同，进而影响到滑动量的反算。