2. STUDY AREAS AND DATA SOURCES In order to demonstrate the capability of the proposed change detection method, two lidar data sets acquired over Tokyo,which is an earthquake-prone area in Japan, on different occasions, were available. Both surveying flights were carried out by Asia Air Survey Co. Ltd in June 1999 and February 2004. Data was provided in 1-m grid format over a dense urban area which includes residential buildings, large buildings, a network of main and local roads, open and green areas as well as trees. Figure 1 shows the acquired lidar data in grid format.