Natural Causes of Landslides

Natural Causes of Landslides

• Climate: Long-term climate changes significantly impact soil stability. Reduced precipitation can lead to landslides, especially when slopes are saturated with water. Mechanical root support is crucial; its absence can lead to soil runoff.
• Earthquakes: Seismic activity contributes to landslides globally. Tectonic plate movements displace soil covering them, leading to landslides.
• Weathering: Rock deterioration, due to natural processes and chemical action from water, air, plants, and bacteria, can weaken slopes, making them susceptible to landslides. Weak rocks slip easily.
• Erosion: Factors like running water, streams, rivers, wind, currents, ice, and waves can erode slope support, making landslides more likely.
• Volcanic Eruptions: Wet conditions during eruptions initiate landslides. Stratovolcanoes are a common cause of volcanic landslides. Volcanic gases can dissolve in groundwater, creating acidic hydrothermal systems that weaken rocks.
• Forest Fires: Wildfires remove protective vegetation, increasing runoff, erosion, and debris flow. Burrowing insects contribute by aerating the soil, which destabilizes it, during wildfire.

Forest Fires

• Wildfires destroy vegetation, reducing soil stability. This increases runoff and erosion.
• Burrowing insects aerate soil, which reduces stability and contributes to landslides during wildfire.

Gravity

• Steeper slopes coupled with gravity can trigger landslides.
• Debris from slopes travels further down steeper slopes

Human Causes of Landslides

• Mining: Blasting techniques greatly contribute to landslides.

Sinkholes

• Sinkholes form when sedimentary rocks dissolve, creating voids. These voids can contain water or air.
• Sinkholes can manifest as holes or depressions.
• Pumped groundwater or broken pipes can contribute to internal erosion, leading to sinkholes.

Signs of Impending Landslides

• Earlier Landslides: Frequent occurrences within a section suggest landslide risk in that area.
• Tension Cracks: These stress-induced cracks, especially above existing landslides, indicate future risk. Cracks above flat terrain indicate fault movement, not landslide.
• Moving Objects: Non-living objects moving or deforming not by human activity indicate landslide development.
• Tree Bending and Curved Trees and Patches: Indicate slope instability and suggest impending landslides. A patch of angled forest on a slope is also a warning sign.

Water and Landslides

• Changes in water flow—like the appearance of springs, seeps, or wet areas in dry regions—can indicate increasing pressure within sloping terrain and increased risk of landslides.
• Groundwater alteration and alteration of drainage systems contribute to landslide risk. Water causes the alteration of pressure within slopes.

Explore the various natural factors that contribute to landslides, including climate change, earthquakes, weathering, erosion, and volcanic eruptions. Understand how these elements interact to destabilize soil and trigger landslides, and learn about the significance of each factor in different environments.