This shows that such a range of thresholds is more suitable to the detection of collapsed buildings. (2) When the threshold ranges from 10% to 40%, the accuracy and kappa coefficients for the difference DEM as shown in Fig. 11a are much better than those for the difference DEM as shown in Fig. 11b. The reason for this is that the DEM created from the pre-seismic topographical map is better than that created from the pre-seismic IKONOS stereo pair. This implies that the incorporation of additional accurate GIS data (e.g., ground points with higher accuracy in both planimetry and height in this study) improves the final accuracy of the detection of buildings that have collapsed in an earthquake. However, with an increase in the threshold (e.g., over 50%), the accuracy for both DEMs does not change. (3) In general, the results show the availability of the proposed method to the detection of collapsed buildings using the pre- and post-seismic IKONOS stereo image pairs.