Spatial and morphometric analysis of a comprehensive dataset of loess sinkholes from a small basin in the Chinese Loess Plateau

Abstract. From a global perspective, the basic mapping and investigation of the loess sinkholes are far less extensive and in-depth than those of karst sinkholes. To some extent, this has limited people's understanding of the morphological characteristics, development patterns, and formation mechanisms of the loess sinkholes. The Chinese Loess Plateau (CLP) features the most typical loess landforms in the world, where tens of thousands of loess sinkholes have developed. However, due to the lack of high-precision and high-resolution survey data, the identification, characterization, and quantification of sinkholes in the CLP are basically blank, which significantly hinders in-depth research on loess sinkholes. In this study, we investigated a typical watershed in the CLP using photogrammetry, airborne laser scanning, and a handheld laser scanner. Based on previous studies, this paper introduces indices and methods for the morphological quantification of loess sinkholes and constructs the first-ever dataset of loess sinkhole morphology containing 1194 records at the basin scale. On this basis, we completed the spatial mapping of loess sinkholes, analysis of distribution patterns, morphological analysis, size-frequency analysis, fitting analysis of different parameters, estimation of subsurface soil erosion, in-depth investigation of typical sinkholes, and quantification of the contributions of different factors to sinkhole development. These efforts provide rich information for a deeper understanding of the morphological characteristics and genesis of loess sinkholes and offer data support for comparative studies with sinkholes in other regions. More importantly, we preliminarily estimate that the subsurface soil erosion triggered by sinkholes in the study area reaches as high as 345 000 metric tons. This finding underscores that loess sinkholes are not only a geological disaster but also a serious form of soil loss, highlighting their undeniable significance in regional soil erosion studies and laying a solid foundation for subsequent research and disaster prevention efforts. Furthermore, we suggest that the integration of airborne laser scanning and handheld laser scanning may represent a new trend in the detailed investigation of sinkholes in the future. This dataset is available on the Zenodo platform (https://doi.org/10.5281/zenodo.14000267, Hu et al., 2025).