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

Abstract. From the perspective of the world, the basic mapping and investigation of the loess sinkhole is far less extensive and in-depth than that of the karst sinkhole survey. To some extent, this hinders people’s understanding of the morphological characteristics, development rules, and formation mechanisms of the loess sinkholes. Chinese Loess Plateau (CLP) has the most typical loess landform in the world, and 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 Loess Plateau are basically blank, which seriously hinders the in-depth study of loess sinkholes. We investigated a typical watershed on the Chinese Loess Plateau using photogrammetry, airborne laser scanning, and handheld laser scanner. Based on previous studies, this paper proposes indices and methods for the morphological quantification of loess sinkholes and constructs the first 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 causes of loess sinkholes and offer data support for comparative studies with sinkholes in other regions. More critically, we preliminarily assessed that the subsurface soil erosion triggered by sinkholes in the study area amounts to as high as 345,000 metric tons. This finding makes it increasingly clear that loess sinkholes are not only a geological disaster process but also a serious soil loss process, highlighting their undeniable significance in regional soil erosion studies and laying a solid foundation for subsequent research and disaster prevention efforts. Moreover, we believe 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. The dataset is available from Zenodo platform (https://doi.org/10.5281/zenodo.14000267).