Describe the general tectonics of himalayan region?5 answersThe Himalayan region showcases complex tectonic processes resulting from the collision between the Indian plate and Asia. This collision led to the formation of the Himalayas, characterized by distinct structural divisions like the Indus–(Yarlung Tsangpo) suture zone, Tethyan Himalaya sedimentary units, Greater Himalaya Sequence (GHS) metamorphic rocks, Lesser Himalaya fold-and-thrust belt, and the Sub-Himalaya Siwalik molasse basin. Active faulting and tectonic deformation are observed in the western Himalayan syntaxis, influenced by transpression processes, contrasting with the east where transtension prevails. The uplift of the Himalayas was driven by the southward migration of plate boundary thrusts, leading to the convergence of the Indian Plate with the Asian Continent at a rate of 58 mm/yr, with the Siwalik Hills experiencing significant uplift along the Main Frontal Thrust.
Reasons for increase in landslide susceptibility in Himalayas?5 answersThe increase in landslide susceptibility in the Himalayas can be attributed to various factors. The fragile lithology, steep slopes, geology, and high topographical roughness of the region make it highly vulnerable to landslides. Intensification of rainfall events, particularly during the southwest monsoon season, has been observed, leading to a higher frequency of landslides. The rise in rainfall over low elevated areas in recent decades compared to historical data has further amplified the occurrence of landslides. Additionally, the fractured nature of rocks, steep river banks, and moderate to steep road cut-slopes in the Himalayas contribute to the increased risk of slope failures, especially triggered by heavy downpours during the monsoon season.
What are the main reasons behind the latest landslide research?5 answersThe latest landslide research focuses on various critical aspects such as understanding probability and consequence, separating site-dependent factors from natural events, determining target risk levels. Additionally, the research emphasizes the impact of snowmelt water on landslide development in mountainous regions due to rising temperatures, historical climatic data analysis, and the association with glacier systems. Furthermore, advancements in landslide hydrology research highlight the importance of considering large-scale hydrological processes, antecedent hydrological information, and feedback between deformation and infiltration processes. Novel predictive models incorporating deep displacement monitoring data and a new risk assessment approach based on orientation vector angles are also key areas of recent landslide research. Improved prediction methods like the CG-SSA-BP neural network aim to enhance accuracy and stability in landslide displacement predictions.
What is the major factor for landslide in India?5 answersThe major factor for landslides in India is heavy rainfall. The high and continuous rainfall in hilly regions triggers slope failures and landslides. The excessive rainfall leads to the saturation of underlying earth material, reducing its cohesive strength and causing major landslides. The geographic and climatic conditions of India, particularly in the Himalayan and northeastern regions, contribute to the high susceptibility of landslides due to the fragile rock conditions, high seismicity, and high rainfall in these areas. Additionally, anthropogenic factors such as unscientific modifications of slopes, mismanagement of water drainage, and unplanned residential developments exacerbate the landslide hazards. Overall, heavy rainfall is the primary factor that leads to landslides in India, especially in the hilly regions.
How to analyze road block due to landslide in a certain area?5 answersTo analyze road block due to landslide in a certain area, a combination of methods can be used. One approach is to evaluate the susceptibility to highway landslides by considering factors such as elevation, slope, aspect, precipitation, and vegetation coverage. Models like Frequency Ratio (FR), Analytic Hierarchy Process (AHP), Logistic Regression (LR), Back Propagation Neural Network (BPNN), and Support Vector Machine (SVM) can be employed for this evaluation. Another method involves on-site defect investigation, special inspection, and finite element simulation calculation to analyze the overall sliding force and damage to the foundation of the bridge caused by landslides. Additionally, the discrete element method and numerical back analysis can be used to study the impact characteristics of rigid retaining walls in blocking landslides and determining the distribution of static and dynamic impact on the retaining wall. Finally, a procedure combining landslide susceptibility maps, road-damage database, and ground-displacement measurements can be used to analyze road damage induced by slow-moving landslides.
Why heavy rainfall is the cause of landslide in hillside development?4 answersHeavy rainfall is the cause of landslides in hillside development due to its impact on slope stability and groundwater dynamics. The intensity of precipitation, along with the hydraulic and mechanical properties of the soil, play a significant role in triggering landslides. Rainfall-induced changes in surface and groundwater conditions reduce slope stability, making the slopes more susceptible to mass movements. Abnormal climatic conditions, including heavy rainfall, can lead to catastrophic landslides. Understanding the relationship between rainfall characteristics and landslide vulnerability is crucial for analyzing and predicting landslide occurrences. The behavior of heavy rainfall patterns before a landslide event can be captured using numerical models like the Weather Research Forecasting (WRF) model. By linking changing rainfall extremes to landslide susceptibility, it is possible to identify risk zones and prioritize critical infrastructure for reinforcement in landslide-prone regions.