Spatial Distribution of Building Stock in Mainland China: A New Perspective from Multiscale Regional Classification

Understanding the spatiotemporal distribution of China’s building stock is crucial for effective seismic risk management. Existing studies, however, often overlook significant regional variations in building characteristics. To address this gap, this study introduces a multiscale regional classification method and develops a building stock assessment model that incorporates demolition factors, utilizing 20 years of data from 114 prefecture-level cities. This integrated approach reveals the spatial distribution and dynamic changes of building stock across various scales in Mainland China. The results show that: (1) The proposed regional classifications correlate with geographical, economic, demographic, and administrative factors, enabling the division of 372 prefecture-level cities into four macroregions or nine refined regions, each with distinct building stock profiles. (2) At a macro scale, China’s total building stock expanded steadily from 34.8 billion m2 in 2001 to 83.3 billion m2 in 2020, an average annual growth rate of 7%. The building stock in the eastern and central regions has consistently exceeded that in the western and northeastern areas, with urban construction surpassing rural. (3) From a detailed perspective, while residential buildings comprise a significant proportion of the total stock, analysis of the refined regions indicates different priorities for risk management: Regions I–VI, which experienced extensive construction in earlier periods, require a focus on their aging building stock, whereas for Regions VII–IX, the emphasis should be on rural and residential buildings. These findings offer valuable data support for risk assessors, aiding the development of more precise, rapid, and targeted seismic risk assessment strategies.