Analysis of Rural Settlement Expansion Patterns and Associated Factors in the Volcanic Lava Region of Northern Hainan from 1990 to 2025

Rural settlements are significant carriers of rural production, living, and land use activities and are also significant subjects for researching regional socio-economic development and spatial structural changes. With regard to the unique topographical environment and transportation situation in the Qiongbei volcanic lava area, a settlement form with prominent topographical constraints and transportation orientation is created. This paper utilizes land use/land cover data from different periods, along with rural settlement expansion patch data, to quantitatively analyze the spatial patterns and expansion characteristics of rural settlements, as well as their influencing factors, from 1990 to 2025 using GIS spatial analysis, buffer gradient analysis (BGA), and multi-order adjacency index (MAI). The research results indicate the following: (1) The spatial pattern of rural settlement distribution in the study area is “peripheral agglomeration and core sparsity,” and the general expansion trend is “rapid in the early period and stable in the late period.” The settlement area expands from 37.21 km2 in 1990 to 80.87 km2 in 2025. (2) The evolutionary pattern of rural settlements in the study area changes from “core–peripheral extension” in the early period to a mixed “core stabilization and peripheral leapfrogging development” model in the later period. The new patches formed in the peripheral areas have obvious discrete features, such as varying land use patterns and differing population densities compared to the core areas. (3) The spatial correlation factors for rural settlement expansion in the study area exhibit stage differences and distinct spatial non-stationary characteristics. During the early period (1990–2008), with strict limitations imposed by the natural material environment, sunlight (interpretability of 0.367) and water systems (0.286) show significant spatial coherence, indicating the great adaptability of rural settlements to the material conditions of the landforms; during the later period (2008–2025), after the implementation of the rural revitalization strategy, the population density (0.135) and transport-related factors become the main spatial correlation factors. The GWR model also shows the percentage of positive and negative influences by influencing factors at each stage and their significant differences in space, proving that human activities break through in the limitations of natural topology in a discontinuous way. According to this research, “inefficient land use” should be understood in a dialectical manner in volcanic geomorphological areas, and spatial optimization should be achieved on the premise of respecting the physicality of volcanic landscapes and rural identity. The research conclusions have important guiding significance for the spatial resilience planning in tropical volcanic areas and traditional settlement culture preservation.