Fig. 4

Stacked vertical displacement rate in a 2007–2010 derived from ALOS data, b 2015–2018 derived from ALOS-2 SM3 data, and c 2015–2018 using ALOS-2 SM3 data from Nos. 10 to 12 and 15 in Table 2. The red arrows in (a) and the areas surrounded by solid lines are obvious subsidence signals. The signals indicated from T1 to T5 in (c) show obvious inter-annual subsidence. d Temporal distribution of InSAR pairs for stacking. Dotted and solid lines show the InSAR pairs for ALOS and ALOS-2; red solid lines show those used for stacking in (c)