Identifying drivers of urban landuse changes in the Wenchuan earthquake-affected area by using night-time light data

To learn the process of urban land evolution before and after an earthquake is vital to formulate the urban reconstruction control policies and recovery measures in the earthquake-stricken areas. However, spatiotemporal evolution and its driving factors of urban land in earthquake-prone areas remains limited due to the scarcity of ground observation data. This research, leveraging night-time light remote sensing imagery and land cover data, conducted a comprehensive analysis of the long-term evolution characteristics of urban land in earthquake-prone areas. It introduced methodologies for assessing the socio-economic impact and the primary natural environmental factors driving urban land evolution in these regions. To validate the proposed methods, the 2008 Wenchuan earthquake-affected area in China was selected as a representative study area. The results indicated that the average Digital Number (DN) values in socio-economically impacted areas showed a trend of rising, falling, and then rising again after the earthquake. DN values in three types of damaged areas including Type II,Type III, and Type IV exceeded pre-earthquake levels. The analysis of determinative factors influencing urban land evolution revealed that slope and elevation were key elements in controlling urban land expansion before the earthquake, whereas factors such as slope, elevation, lithology, and faults had a stronger influence on urban land expansion after the earthquake. It can be seen that, in view of the differences in the natural conditions of regions for post-disaster reconstruction, the local government need to actively adjust and adapt to urban spatial planning, so as to leverage the scale effect of large-scale inputs of funds, facilities, human resources and other factors after the disaster, thus enhancing resilience and recovery efficiency in response to disaster impacts.