Geologic Hazards in the Philippines

Location and Geology of the Philippines

• The Philippines is located in an archipelago characterized by mountainous terrains and is prone to typhoons that bring heavy rain.
• The combination of these two conditions can cause landslides and sinkholes due to the topographic and geologic composition of the land.

Geological Hazards

• Geological hazards are natural phenomena that cause major problems worldwide.
• The expansion and development of cities have increased the impact and damage due to geological hazards.
• Most geological hazards are related to natural conditions, but some may be due to human activities.

Landslides

• Landslides are also known as mudslides or debris avalanches and occur on inclined terrain.
• Landslides are ground movements on sloping terrain and do not occur on flat ground.
• Gravity induces the land to move downward, and rain can aggravate this process.
• Structures built on steep-slope mountains have a high vulnerability to landslide hazards, especially during heavy rains.
• Areas with steep slopes, dense population, and denuded terrain are highly susceptible to rainfall-induced landslide hazards.

Types of Landslides

• Soil Creep Landslide: a very slow downslope movement of particles that occurs in every slope covered with loose, weathered material.
• Slumping Landslide: a downward movement of rock debris as a unit, usually along a curved plane of failure.
• Debris Flow Landslide: a landslide of water-soaked mass of rock and soil that slides down the slope.
• Rock Fall Landslide: a sudden slide caused by heavy rain, where the rock on the slope loosens and then slides down the slope.

Sinkholes

• Sinkholes can occur on elevated or flat surfaces and can range from massive to barely noticeable.
• Sinkholes can leave a dent, a hole, or a body of water on the ground.
• The actual difference between landslide and sinkholes is in their composition and type of terrain.