Homeowners in Japan may need to check their building's structural integrity. Environment Ministry officials have released data showing unprecedented subsidence since the March 11 earthquake. The official said following the quake nearly 6,000 square kilometers of land, thank by more than two centimeters. That's 1,000 times the previous year's figure and the highest since records began in 1978. About half the 30 areas and 20 prefectures were recorded as thinking enough to impact on building stability. Ministry officials reported Kess Senama and Miyagi prefecture sank the most by 73.8 centimeters. Residents of Tahoku and Kanto experienced subsidence by more than 10 centimeters in seven different areas. Officials attributed this subsidence to the March 11 earthquake. The express concerns the subsidence might still spread and cause further damage to buildings.