## 5 Case Study of Landslide Prone Regions  
### India  
Several landslides have struck the Himalayan area, and a sample of the more well-studied and destructive landslides are highlighted below. The majority of research has taken place in Uttarakhand [63]. Some large landslides in Uttarakhand happened in the Okhimath area in Mandakini Valley, which was severely devastated by a landslide caused by intensive rainfall in August 1998 [64]. A total of 466 landslides were caused in all, resulting in 103 fatalities and the destruction of 47 communities. Subsequently, a cloudburst in Mandakini Valley in July 2001 caused more than 200 landslides, killing 27 individuals and affecting over 4000 people. To detect a landslide immediately after its occurrence, the OB method has been used for making landslide inventory database from previous pictures. In Okhimath, Uttarakhand, data from the 1998 landslide inventory were related to field data collected after the landslide [65], as shown in Figure 6. In the research, 73 landslides were discovered using Resourcesat-1 LISS-IV multispectral data (5.8 m) and a 10-m Cartosat-1 derived digital elevation model (DEM). In terms of the number of landslides, this semi-automatic method resulted in an accuracy of 76 percent for recognition and 69 percent for categorization using a semi-automatic approach. The Darjeeling region of West Bengal and Sikkim has seen the highest number of recorded landslides in the country's northeastern region. Landslides have occurred in the Darjeeling area on many occasions in the past, with the first significant documented event being in 1899, which resulted in the deaths of 72 people. Subsequently, landslides occurred in 1950 (in which 127 people perished) and 1968 [66] (667 people died). The majority of landslides in the Indian Himalayan area are shallow in character, with rainfall serving as the main triggering cause in the majority of cases. Precipitation analysis for the purpose of predicting landslide occurrence may be accomplished via the estimation of minimum rainfall conditions, subsurface monitoring, or slope stability analysis. In terms of minimal rainfall conditions, often known as thresholds, two types of methods may be distinguished: empirical and physical [67]. The majority of landslides in the Indian Himalayan area are shallow in character, with rainfall serving as the main triggering cause in the majority of cases. Precipitation analysis for the purpose of predicting landslide occurrence may be accomplished via the estimation of minimum rainfall conditions, subsurface monitoring, or slope stability analysis. In the Himalayan area, it has been proposed that antecedent rainfall, lasting between 15 and 30 days, has a significant impact on destabilizing slopes, resulting in landslides being triggered by subsequent rainfall of short duration (24-72 h). There has been little research on rainfall thresholds in the Indian Himalayas, and more study on calculating and studying local and regional thresholds is needed [68]. It is self-evident that Kerala's diverse climatic conditions enhance slope failures [69]. In Kerala, the greatest mass movements originate on hill slopes along the Western Ghats scarps [70,71] apart from the coastal cliffs. Shallow landslides and mudflows are much more frequent than massive landslides and debris flows. Typically, debris flows lead to the formation of very low streams, the reopening of naturally clogged drainage routes, and the enlargement of streams. The Wayanad and Kozhikode districts, situated north of the Palakkad Gap, are more prone to deep-seated landslides, which may be attributed to the state's greater rainy season [72]. Historical archives include only indirect evidence of landslides in the past, which were most likely limited to seasonal rainfall associated with severe parts of the course [73]. Human impacts, such as reforestation, conservation tillage and blockage of small streams, and the growth of crops incapable of adding root cohesiveness on steep slopes, increase the process.