Methods for Monitoring Fast and Large Gradient Subsidence in Coal Mining Areas using SAR Images: A Review

Ground subsidence caused by coal mining may lead to seriously damage to ecological environment system and economic and social development. SAR image interferometry technology has been widely used for monitoring coal mining subsidence. However, at present it is still a challenge for it to monitor fast and large gradient subsidence. In order to obtain fast and large gradient subsidence using SAR images, some scholars have resorted other methods and technology which doesn’t just depend on the interferograms, and they have obtained better results. In a summary, these methods and technology can be grouped into three main categories: (i) Combining InSAR with coal mining subsidence prediction models; (ii) Using SAR image amplitude information offset tracking technology; (iii) Combining InSAR with terrestrial 3D laser scanning technology. In this paper, the technology features, research progress, applications and limitations of these methods are analyzed; and some potential prospects of using SAR images to monitor fast and large subsidence in coal mining areas are discussed in the end.