1. Slope Steepness and Stability: Areas with steeper slopes are more susceptible to landslides during heavy rainfall. These areas are less stable and can easily fail when the ground becomes saturated with water.
2. Soil Type: Soil composition plays a significant role in landslide occurrence. Certain soil types, such as loose soil, sandy soil, and clay-rich soil with low permeability, are more likely to experience landslides when subjected to heavy rainfall.
3. Drainage and Water Accumulation: Inadequate drainage systems can lead to water accumulation and increased pore water pressure in the soil, reducing soil strength and making it prone to failure and landslides. Areas with poor drainage and lack of proper water diversion channels are more vulnerable during heavy storms.
4. Vegetation: Dense vegetation can help stabilize slopes by holding the soil together and reducing erosion. Areas that have been cleared of vegetation, such as for development or agriculture, are more susceptible to landslides.
5. Geologic Conditions: The underlying geology of an area can influence landslide occurrence. Factors like the presence of weak rock formations, faults, and natural fractures can contribute to slope instability, particularly during heavy rainfall.
6. Preexisting Conditions: Areas that have experienced previous landslides or are known to be in landslide-prone zones are more likely to experience further landslides, even during moderate rainfall events.
7. Human Activities: Human activities, such as improper land use, deforestation, and construction without proper engineering and erosion control measures, can alter natural drainage patterns and slope stability, making areas more susceptible to landslides during heavy rainfall.
