8 OTHER RELATED GEOLOGICAL HAZARDS - landslide.pptx
- 2. LEARNING TASKS: 1. DESCRIBE RAINFALL-INDUCED LANDSLIDE 2. IDENTIFY THE CAUSES OF LANDSLIDE 3. ANALYZE THE EFFECTS OF LANDSLIDE
- 3. ACTIVITY: MAKE A GRAPHIC ORGANIZER AND IDENTIFY SOME CAUSES OF LANDSLIDE. LAND SLIDE
- 4. RAINFALL-INDUCED LANDSLIDE A massive outward and downward movement of slope-forming materials. Movements of rocks and soil masses. Initiated when a section of a hill slope or slopping section of a sea bed is rendered too weak to support its own weight. Triggered by other natural hazards such as prolonged, heavy rainfall or by other sources of water which increase the water content of the slope materials.
- 5. RAINFALL-INDUCED LANDSLIDE Caused by earthquake or volcanic eruption. Susceptibility of hill slope to landslide is developed as a result of denudation of mountainsides which removes the trees or ground cover that holds the soil, or alteration of the surface of the ground like grading for roads or building construction.
- 6. CAUSE OF LANDSLIDE 1. NATURAL CAUSES OF LANDSLIDES - Groundwater pressure acting to destabilize the slope - loss or absence of vertical vegetative structure, soil nutrients, and soil structure - erosion of the toe of a slope by rivers or ocean waves - weakening of a slope through saturation by snow melt, glaciers melting or heavy rains
- 7. CAUSE OF LANDSLIDE 1. NATURAL CAUSES OF LANDSLIDES - earthquakes adding loads to barely stable slope - earthquake-caused liquefaction destabilizing slopes - volcanic eruptions
- 8. CAUSE OF LANDSLIDE 2. HUMAN ACTIVITIES - deforestation, cultivation and construction, which destabilize the already fragile slopes. - vibrations from machinery or traffic - blasting (mining) - earthwork which alters the shape of a slope, or which imposes new loads on an existing slope.
- 9. CAUSE OF LANDSLIDE 2. HUMAN ACTIVITIES - in shallow soils, the removal of deep-rooted vegetation that binds colluvium to bedrock ( Kaingin farming system) - construction works, agricultural or forestry activities change the amount of water infiltrating the soil.
- 10. EFFECTS OF LANDSLIDES CAUSED PROPERTY DAMAGE INJURY AND DEATH AND ADVERSELY AFFECT A VARIETY OF RESOURCES COST TO REPAIR STRUCTURES LOSS OF PROPERTY VALUE DISRUPTION OF TRANSPORTATION ROUTES MEDICAL COSTS IN THE EVENT OF INJURY
- 11. EFFECTS OF LANDSLIDES QUANTITY AND QUALITY OF WATER AVAILABILITY GEOTECHNICAL STUDIES AND ENGINEERING PROJECTS TO ASSESS AND STABILIZE POTENTIALLY DANGEROUS SITES CAN BE COSTLY
- 12. THANK YOU!