Average-DInSAR method for unstable escarpments detection induced by underground coal mining

•Average-DInSAR overcomes low coherence and noisy of DInSAR, especially for shorter X- or C-band SAR data.•Underground coal mining affects the landslide of steep cliffs.•Before the slope is destroyed, displacement detection can be carried out with a higher revisit frequency.•The enhancement of the deformation phase superposition is benefit to makes up for the void of the non-interference result in part of the interferogram.