Coupling coordination and spatiotemporal dynamic evolution between urbanization and geological hazards?A case study from China

Investigation of the coupling coordination between urbanization and geological hazards is an important component in fostering environmentally sustainable development. This study constructed the comprehensive index system and developed the improved coupling coordination degree (CCD) model, Moran's I and projection pursuit model based on genetic algorithm to quantitatively investigate the dynamic mechanism and spatiotemporal distribution of coupling coordination between two subsystems within the context of the Five-Year Plan. Results showed that the comprehensive level of urbanization subsystem followed a continuous upward trend, and the geological hazard subsystem changed from a decreasing (2000-2010) to a rising (2011-2017) trend. A U-shaped relationship existed between two subsystems. And the CCD between two subsystems was higher in northeastern than that in southwestern China. Moreover, the significant spatial dependency existed in CCD. Driving by terrain, rainfall, vegetation cover, and human activities, the provinces in southwestern China exhibited low-low (L-L) clustering, while that in northeastern China showed high-high (H-H) clustering. In the past 17 years, the provinces in transitional and balanced development increased by 14.7% and 8.8%, and that in unbalanced development decreased by 23.5%. Overall, the provinces with low CCD were shrinking and the provinces with high CCD were extending from northeastern to southwestern China, meaning that the state of coupling coordination was changing from unbalanced to transitional development.