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LANDSLIDES

Includes all varieties of mass movements of hill slopes and can be defined as the downward or upward movement of slope forming materials composed of rocks, soil, and regolith along surface of separation by falling, sliding, and sliding, either slowly or quickly from one place to another.

EARTHQUAKE

When plate tectonics move the soil that covers moves with it. When shaking occur on areas with steep slopes. Many times the soil slips causing landslides.

Heavy Rain

Storm water runoff saturates soils on steep or infiltration causes a rapid rise in ground water levels.

Forest Fire

causes soil erosion and induce floods and landslides due to the destruction of the natural vegetation.

Volcanoes

The condition commonly prevail after eruptions that kill vegetation over extensive areas and spread loose rocks over the landscape.

Over development

Logging, residential and infrastructure development and other activities continue to expand on slopes highly prone to landslides.

Deforestation

steep slopes may temporarily reduce evapotranspiration and lessen root reinforcement thus potentially enhancing landslide susceptibility.

Inappropriate Drainage System

When clogged drainage pipes cannot properly drain groundwater from the landslide slopes, this may lead to landslide occurrence.

Falls

are landslides that involve the collapse of material from a cliff or steep slope, usually involve a mixture of free fall through the air, bouncing or rolling.

slide

happens when a section of soil or rock gives way and moves down a slope. The material moves as a single mass along a slippery zone.

Translational slides

can contain loose sediments or large slabs of bedrock.

Rotational slides

(slumps) are landslides that occur along a curved or spoon-shaped surface.

TOPPLES

This is characterized by the tilting of rock without collapse, or by the forward rotation of rocks about a pivot point.

Flows

are landslides that involve the movement of material down a slope in the form of a fluid, often leave behind a distinctive, upside-down funnel shaped deposit where the landslide material has stopped moving.

slurry (wet) flows

These occur in areas where the soil remains saturated with water for long periods of time.

Granular (dry) flows

are not water-saturated, but rather are supported by grain to grain contact.

Ground Subsidence

is a general term for downward vertical movement of the Earth's surface, which can be caused by both natural processes and human activities, involves little or no horizontal movement, which distinguishes it from slope movement.

Collapse

is the relatively fast opening of the land surface and movement of surface materials into the underlying cavities.

Sinkholes

are formed when the land surface above collapses or sinks into the cavities or when surface material is carried downward into the voids.

Dissolution

result when soil cover is thin and highly permeable

Cover subsidence

form when sandy, permeable sediment sits on top of limestone bedrock.

Cover collapse

Occur suddenly and without warning.