The classification and naming of of the Hongshanwan landform in the Zhangye UNESCO Global Geopark have long been contentious. Through research and comparison, it is found that there are significant differences in geomorphic forces, landform morphology, material composition, landform development, and evolutionary processes compared to the Danxia landforms. Following the principles of rock landform classification and naming, it is currently appropriate to refer to them as the Hongshanwan landforms. As a subcategory of red bed landforms, they should be listed alongside the Danxia landforms. This article proposes the definition of Hongshanwan landforms as follows: they are characterized by internal forces of structural tilting, with surface sheet flow as the main external force, and are formed by the combined action of external forces such as weathering, erosion, and gravity, resulting in gentle slopes with colorful rhythmic sedimentary features typical of red bed landforms. These landforms are mainly composed of red Cretaceous terrestrial mudstones and sandstones with interbedded grayish-blue and grayish-green colors. The main internal and external forces shaping the landforms are structural tilting and surface sheet flow, respectively. The landform morphology is characterized by gentle undulations, colorful rhythmic sedimentary features, and the development of micro-landforms such as mud stalactites, mud waterfalls, and small earth pyramids. Depending on the combination of stratum dip and slope morphology, the landscape types of Hongshanwan landform can be categorized into over ten types, including horizontal color stripe type, inclined color stripe type, vertical color stripe type, rainbow type, inverted rainbow type, wave type, scallop type, pleated skirt type, and composite type. Hongshanwan landforms are mainly distributed in arid and semi-arid regions, particularly in the central areas of red beds basins closely related to mountainous regions, including Jiuquan, Zhangye, and Lanzhou basins in front of the Qilian Mountains, the Junggar Basin at the southern foot of the Altai Mountains in Xinjiang, and the Andes Mountains in South America.

The thesis uses local chronicles as the basic document and uses quantitative analysis methods to study the history of disasters in Guangdong and Guangxi during the Republic of China. According to research, the floods and droughts are the most common, while wind disasters, pests and earthquakes are also more frequent, while animal disasters, hail disasters, snow disasters and frost disasters are relatively rare.The trend of disasters gradually increased, with six periods of severe disasters, especially the two periods of severe disasters in the 1940s. There are obvious regional differences in the spatial distribution of disasters, floods and wind disasters are common along rivers and coastal areas, droughts and pests are more frequent in inland areas, animal disasters are concentrated in remote mountain areas, and other disasters are scattered around. Due to the difference of spatial and temporal distribution of natural disasters in Guangdong and Guangxi, the destructiveness of various natural disasters is also different. Flood and drought are the most destructive, followed by wind disasters, pests, and again for the earthquake, animal disasters and other disasters. At the same time, the natural disasters in Guangdong and Guangxi are different. Guangdong is more serious than Guangxi in flood, wind disasters, pest and earthquake, but less serious than Guangxi in drought and animal disaster. To sum up, the natural disasters in Guangdong and Guangxi were frequent and serious, and the overall disaster situation was not optimistic.

According to the survey data of geological disasters, karst collapse has become one of the main geological disasters that restrict the social and economic development of Guangzhou city. More than 700 karst collapses and related data in Guangzhou city over the past 50 years are statistically analyzed by the Guangzhou city geological disaster investigation and risk assessment Project. Based on the analysis of the spatial distribution of soluble rock and karst, the distribution, morphology and controlling factors of karst collapse in Guangzhou city are systematically studied. The results show that the development of karst collapse in Guangzhou city is mainly controlled by the degree of karst development, the structure of the cover lying geotechnical body, geological structure, hydrogeological environment and the intensity of human engineering activities. The direct triggering factors of karst collapse mainly include drainage of groundwater by mining and foundation engineering construction, excessive exploitation of karst groundwater, drilling construction, ground vibration loading, water and mud inrush from mining tunnel, heavy rainfall infiltration, and alternating effects of drought and flood. The research results provide an informative geological basis for the prevention and control of karst collapse in Guangzhou city.

Collapsing hill is the most severe type of soil erosion in southern China. This study investigated the soil physical properties and particle size composition of different landforms in Gangwei Collapsing Hill, Xinyi City, and explored the changes in soil physical properties and particle size in different landforms, as well as reveals the development mechanism of collapse erosion. The results showed that: (1) There are significant differences in physical properties such as water content, bulk density, specific gravity, and porosity in soil samples from different landforms of Gangwei Collapse Hill. The soil texture of the upper collapsing wall and colluvial deposit is relatively dense and compact, and the degree of water transformation is relatively weak; the loose soil texture of soil samples from scour channel and alluvial fan indicates a strong participation of water flow. (2) The particle size composition shows that the soil sample of Gangwei collapse hill is gravel containing sandy soil. The soil samples from the collapsing wall exhibit the undisturbed soil characteristics of the weathered granite crust, while the soil samples from the colluvial deposit are the product of the combined erosion of gravity and hydraulic forces, while the soil samples from channel and alluvial fan exhibit sedimentary characteristics dominated by flowing water. (3) The uniformity coefficient and curvature coefficient indicate that the accumulation time of collapsed soil is relatively short. The development age of the collapsing hill is relatively young, and the geomorphic form and vegetation coverage of the collapsing hill also indicate that it is in the stage of development.