Photo taken on Feb. 26, 2012 shows cracks on the wall of a house due to the land sink in Yuejiaqiao Town, Yiyang City of central China's Hunan Province. Nearly 700 cave-ins had been reported in Yuejiaqiao as of Feb. 24 this year for an extensive karst ground subsidence occurred in the town, leaving dozens houses damaged, and farmlands and riverbeds sunk as well. Some 1,200 locals were affected by the cave-in and lived in trouble.