2.Current status and main features Fig.1 shows the distribution of the large and median size cities in China where land subsidence is remarkable. The land subsidence can be classified into the following three types of geographic regions (Table 1):the coastal plain and river delta regions,such as Shanghai,Tanjin, Ningbo,Suzhou,Wuxi,and Changzhou;the plain regions in front of major mountains,such as the North China Plain and Songliao Plain;regions in valleys and basins among mountains,such as Xi'an and Taiyuan.2. Current status and main features Fig. 1 shows the distribution of the large and median size cities in China where land subsidence is remarkable. The land subsidence can be classified into the following three types of geographic regions (Table 1): the coastal plain and river delta regions, such as Shanghai, Tanjin, Ningbo, Suzhou, Wuxi, and Changzhou; the plain regions in front of major mountains, such as the North China Plain and Songliao Plain; regions in valleys and basins among mountains, such as Xi’an and Taiyuan