DRRR FINALS

• Geological hazards and other causes

  -        Caused by natural phenomena, significant global problem, especially due to urban expansion and development.
• Landslide – the downward ground movement on a sloping terrain caused by gravity, also comes in a scientific name “landmass”.
• natural causes of landslides:

  climate

  earthquake

  weathering

  erosion

  volcanic eruption

  forest fires

  gravity
• Climate

  -        Long term climatic changes can significantly impact soil stability.

  -        A significant upsurge in precipitation or ground saturation would dramatically increase the level of  ground water.
• Earthquake

  -        Seismic activities for a long time may cause to landslides across the globe, any moment tectonic plates move, the soil covering them also moves along.

  -        When earthquake strikes areas with steep slips leading to landslides.
• Weathering

  -        Is the natural procedure of rock deterioration that leads to weak, landslide susceptive materials.

  -        Brought about by the chemical action of water, air, plants and bacteria, when the rocks are weak enough they slip away.
• Erosion

  -        caused by sporadic running water such as streams, rivers, wind, currents, ice and waves wipes out latent and lateral slope support enabling landslides to occur easily.
• Volcanic eruption

  -        if an eruption occurs in a wet condition the soil will start to move downhill instigating landslide.

  -        Stratovolcano is a typical example of volcano responsible for most landslides across the globe.
• Forest fires

  -        wildfires removes the protective ability of vegetation which increases runoff, erosion, and debris flow because the water cannot penetrate through the soil thus carrying the debris downslope. burrowing insects also play a role by aerating the soil destabilizing it during a wildfire because they tend to seek for cooler soil to survive.
• Gravity

  -        steeper slopes coupled with gravitational force can trigger a massive landslide, can also cause the debris to flow farther from foot of the area.
• Mining

  -        mining activities that utilize blasting techniques contribute mightily to landslides, vibrations affect a part of the partly of soils in susceptible areas.
• Clear cutting

  -        is a technique of timber harvesting that eliminates all odd tress from the area.
• human causes landslides:

  mining

  clear cutting
• Types of landslides

  Ø  soil creep

  Ø  slumping

  Ø  debris flow

  Ø  rock fall
• Soil creep landslide – a very slow downslope movement of particles that occur in every slope covered with loose, weathered material.
• Slumping landslide – a downward movement of rock debris, usually consequence of removal of buttressing earth at the foot of a slope of unconsolidated material.
• Rockfall landslides – are sudden slides caused by heavy rain the rock on the slope loosens and then slides down the slope.
• Debris flow – happens when slope becomes saturated with water, this triggers a landslide of water-soaked mass of rock and soil that slides down the slope.
• Fire triangle (fuel, heat, oxygen)
• 1.  Fuel – any material that can be burned such as solid, liquid or gas. Combustion takes place when the fuel is converted into gaseous state as moisture is removed. This happens when vapor is escaping from any combustible material.
• 1.  Heat – is an energy that flows through object. Enough amount of heat would free the vapor from solid and liquid forms of fuel. The lowest temperature needed to form an ignitable mixture in air near the surface of the liquid is called the “flash point”.
• 1.  Oxygen – is an element, estimated 21% of it can be found in the air. During combustion process chemical reaction takes place, oxygen is released and serve as an oxidizing agent for combustible materials. Without an oxidizing agent like oxygen there will be no fire even if heat and fuel are present.
• The theory of fire extinguishing is based on removing any of the elements in the fire triangle to suppress the fire.

  1.  Removing the heat

  2.  Removing the fuel

  3.  Removing the oxygen
• Natural causes of fire

  -        Lightning

  -        Volcanic activities

  -        Spontaneous combustion
• Human-made causes of fire

  -        Cooking equipment

  -        Heaters

  -        Smoking in bedrooms

  -        Candles

  -        Curios children

  -        Faulty wiring

  -        Barbecues

  -        Flammable liquids

  -        Lightning