Landslides are considered to be one of the most harmful geological disasters in the world, bringing an enormous loss of property and life each year 1. Landslides in high-order position areas typically pose huge dangers with their kinetic and gravitational potential energy, yet they can be difficult to recognize on time, particularly if they are concealed 2. Landslides are always accompanied by devastating disasters and can even bury entire villages. For example, the Xinmo landslide in 2017 buried the whole village with over 100 inhabitants in just a few seconds 3. Numerous landslides occur each year in the mountainous area of Southwest China, particularly in Sichuan province, threatening the ecology, life and infrastructure 4.
Systematic research on landslides began in the 1960s in order to try and qualitatively understand landslides 5. Subsequently, numerous studies were performed, making substantial progress and transforming landslide research from qualitative to quantitative over the next 20 years 6–8. Following this, RS (Remote Sensing) and GIS (Geographic Information System) technology has gradually become an important tool in landslide research with the development and popularization of computer technology and the accuracy improvements in satellite imagery 9,10. Since the beginning of the 21st century, studies on landslides have become more in-depth and focus on analyzing the relevant mechanisms 11–13, with a switch from passive investigation to active exploration, including in-situ observations 14, satellite interferometry 15, machine learning algorithms 16, etc. Such advanced technical approaches have increased the effectiveness of the identification, monitoring and management of landslides, greatly reducing the damage of landslide disasters 17. Therefore, the early identification, monitoring and immediate hedging of huge landslides has have become the key themes of landslide research 18.
Early landslide identification in the late 1970s focus on recognizing the characteristics of landslides via Landsat images 19 as well as the analysis and observation of landslide occurrence characteristics by integrated approaches for forecasting 20. Since the 1990s, the geologic evaluation of landslide stability in engineering was typically preformed to ascertain the shear surface, failure plane, internal slider movement and hydrogeological regime of the landslide. However, such geophysical surveys are usually high in costs 21. Thus, GPS, phototopography, and InSAR have been important tools to timely monitor the activities of existing landslides 22. In the years following 2000, studies were able to determine the landslide type and quantify changes via high resolution remote sensing images 23,24. However, as optical images are limited by the influence of clouds and atmosphere etc., the combination of optical images and SAR for the detection and monitoring of landslides has been of great significance in recent years 25,26. This technique is not only limited to the monitoring of landslide changes, but can also predict the evolution based on highly-developed models 27,28. The evolution and development of some huge landslides have much common ground which was mainly creep sliding in early stage and rupture at crucial moment, so some landslides have been successfully predicted according to study on early creep sliding 29.
Recent research on landslide identification generally integrates various methods, including the combination of optical and microwave remote sensing 30, as well as the combination of micro and macro approaches, allowing for the more precise early identification of landslides 31,32. Although physical model experiments are still labor and cost-intensive for landslide monitoring and such approaches are important and have made great advancements 33, model scholars also prefer the application of machine learning models 34. In particular, machine learning models exhibit a better performance than other mathematical models, and the representation of different machine learning models is variant 33. In addition, the majority have a strong reliability, particularly improved models that perform better 35. Some organizations require the monitoring and prediction of multiple landslides, thus early warning systems have been developed 36. However, considering the complexity of engineering geological conditions of an individual landslide, it is difficult to replace individual monitoring with generalized systems. Therefore, in the current study, we focus on the monitoring of a single landslide. Moreover, the existing literature generally absorbed in existing landslides, such as the Xinmo landslide in 2017 37 and the Baige landslide in 2018 38. The early identification of potential landslides can avoid the occurrence of landslides in a timely manner. In particular, potential landslides can be determined by integrating optical and radar imagery to carry out a series of in-depth evaluations, followed by the implementation of long-term forecasts and regular investigation. The current research is based on an comprehensive integration of previous studies, providing important guidance to reduce losses of landslides timely.
Landslides are the most common geological hazards in Southwest China, particularly high-order position and large-scale landslides. Diexi in southwest China, with frequent earthquakes and a complex geo-structure, is selected as the study area of this work. The suspected potential landslide areas are first identified by SBAS-InSAR data, followed by the recognition of these suspected potential landslides by multiple-source remote sensing images to further identify the suspected potential landslides. Finally, Tuanjiecun suspected potential landslide is selected as the key survey target and field investigations are conducted. Three key steps are performed after the selection of the Tuanjiecun potential landslide: a) the analysis of over 50 months of SBAS-InSAR data; b) high precision image comparisons over a 10-year period and c) differential DEM analysis at various periods. Following this, the deformation velocity of the first 48 periods from SBAS-InSAR data are used to predict the future deformation velocity by machine learning and verified by the subsequent 10 periods. The proposed prediction model can be applied to future deformation predictions and of great significance to in-depth landslide studies.