# Factors Affecting the Stability of Loess Landslides: A Review
## 4 Discussion  
Loess landslides cause significant losses to the national economy, human life, and property every year. Loess landslides are not widespread; they are confined to specific geographical areas, but there are significant number of people living in the Loess Plateau region in China. Emergency rescue during landslide hazards is a major challenge due to the unique geographical location, large area, and high population density. Therefore, it is crucial to conduct a thorough study to understand the causes and mechanisms of loess landslides. The improvement of monitoring, simulation, early warning systems, prevention measures, and control strategies for loess landslides is also necessary. Analyzing landslides requires multidisciplinary integration; it cannot be achieved by a single method or a few underlying principles. There are still many problems to be addressed. Firstly, correlating geophysical interpretation with hydrological or geotechnical parameters (e.g., water content, pore water pressure, and shear strength) is still challenging. Secondly, it is difficult to integrate remote sensing parameters with subsurface measurements. Thirdly, correlating geophysical measured parameters (e.g., resistivity) with geochemical measured ions is an obstacle. Additionally, the accuracy of geophysical methods (e.g., SRT and ERT) in measuring trace elements needs improving. Moreover, using electrical methods to reduce the multivalence of stratigraphic layering is still in development. Multi-disciplinary cooperation and the integration of multiple parameters are significant for these challenges. These parameters can be obtained from several places, such as the surface and subsurface and at high altitudes. Mechanical, electrical, seismic, and infrared methods are used toobtain these parameters. This emphasizes the importance of integrated approaches for the study of landslides in the Loess Plateau region. Conducting independent studies with limitations for specific targets may result in multivalence. For example, the increase in resistivity observed in cracked soils cannot be only attributed to the decrease in soil water content [33]. When collecting and analyzing parameters, accuracy, practicality, and non-destructiveness are essential considerations. The most important requirement is that the data collected for scientific purposes must be reliable and accurate. Additionally, data must be easily collected by different methods. Moreover, damage or disturbance are inevitable when collecting data for landslides. To assess the structural integrity of the landslide, techniques such as trenching and drilling are not suitable. A major challenge of new techniques and improvements in equipment is to determine the optimum approach obtaining slope parameters whilst minimizing disturbance. The universality and practicality of the methodology needs to be improved. The data processing and inversion methods are the main focus of the methodology. As mentioned earlier, there are several data processing methods, e.g., correlation analysis, multi-parameter coupling, two-dimensional finite unit, smoothing constrained least squares, numerical simulation, and inverse analysis. However, there is currently no standardized specification for these methods, and there is no method that fully adapts to the realistic situation in data processing and inverting. Further studies are significant in the challenge multi-parameter joint inversion, in which the interaction of several factors has to be considered. The main challenge is the joint inversion of field resistivity and other electromagnetic/hydrogeological parameters and the methodology of integration with other geophysical methods [36]. Field experiments are often more convincing than lab experiments; thus, valid methods in lab experiments need to be verified in realistic field conditions. To provide a more intuitive understanding of the morphological characteristics of loess landslides, many research studies have developed 3D and 4D models.