DRRR

• geological hazard 


  are natural disasters causing a great loss of life and destruction of properties and infrastructures. Include earthquake, volcanic eruptions, tsunami landslide, and sinkhole.
• landslide 


  is a phenomenon where soil and rock is moved out of place along a slope by gravitational force usually on unstable slope It can be either natural or man-made reasons.
• slope angle, climate, weathering, vegetation, overloading, geology, melting of accumulated snow, and slope stability.


  Some factors which influence landslide are usually natural, these include
• Geological Hazards

  • Earthquake
  • Volcanic eruptions
  • Tsunami
  • Landslide
  • Sinkhole
• Landslide


  Phenomenon where soil and rock is moved out of place along a slope by gravitational force usually on unstable slope. Can be either natural or man-made.
• Factors influencing landslides

  • Slope angle
  • Climate
  • Weathering
  • Vegetation
  • Overloading
  • Geology
  • Melting of accumulated snow
  • Slope stability
• Due to human activities, landslides have currently increased in frequency. Clear cutting is a primary human cause wherein all kinds of tree are uniformly cut down in a specific area.
• Retrogressive Landslide


  Happen when the top layer of soil begins to slide down
• Piecemeal Landslide


  Landslides that happen at smaller areas at a time
• Reactivated Landslide


  Happen when the area of a previous landslide incident is disturbed
• Sinkhole


  Derived from an evolution process, also described as sink, swallow hole or cenote
• Common soluble rocks


  • Rock salt
  • Gypsum
  • Limestone
• Types of Sinkholes

  • Dissolution Sinkhole
  • Cover collapse sinkhole
  • Cover-Subsidence sinkhole
• Dissolution Sinkhole


  Happen when a cavity is formed due to the erosion of soluble rock
• Cover Subsidence Sinkhole


  Occur when a large material cover a soluble rock and fills the voids, leading to the erosion of sediment downward
• Cover-collapse Sinkhole


  Happen when clay material covers a layer of carbonate rock
• Hydro meteorological hazards


  A process or phenomenon of atmospheric, hydrological or oceanographic nature that may cause loss of life, injury or other health impacts, property damage, loss of livelihoods and services, social and economic disruption, or environmental damage
• Hydro meteorological hazards

  • Tropical cyclones (also known as typhoons and hurricanes)
  • Thunderstorms
  • Hailstorms
  • Tornados
  • Blizzards
  • Heavy snowfall
  • Avalanches
  • Coastal storm surges
  • Floods including flash floods
  • Drought
  • Heatwaves
  • Cold spells
• Hydro meteorological conditions also can be a factor in other hazards such as landslides, wildland fires, locust plagues, epidemics, and in the transport and dispersal of toxic substances and volcanic eruption material
• Typhoon


  Forms when warm ocean water evaporates rapidly, usually occurs in the Western Pacific, takes a spiral form and travels while rotating, usually has a diameter of not less than a hundred kilometers, the warmer the ocean, the bigger and stronger typhoon is formed
• Cumulus clouds


  • Good indicators that thunderstorms are likely to happen, often seen during summer and thunderstorms brought by these clouds happen in the afternoon as the clouds accumulate with the heat throughout the day
• Cirrus clouds


  • Strands-like clouds that form almost above 20,000 feet in the sky, indicate a change in weather, usually from a warm weather to a bad weather, in the next 12 to 48 hours
• Lenticular clouds


  • Look like wave clouds, indicate the presence of strong winds in the upper part of the atmosphere, often indicate a larger incoming storm
• Dark sky


  • Often suggests a bad weather incoming
• Drop in barometric pressure gauge

  • Indicates rain or snow
• Cyclone


  Tropical Cyclone (TC), also known as "Cyclone", is the term used globally to cover tropical weather systems in which winds equal or exceed "gale force" (minimum of 34 knot, i.e., 62 kmph), are intense low pressure areas of the earth atmosphere and are extreme weather events of the tropics, characterised by a large low pressure centre and numerous thunderstorms that produce strong winds and flooding rain, feed on heat released when moist air rises, resulting in condensation of water vapour
• Destruction caused by Cyclones

  • Strong Winds/Squall
  • Torrential rains and inland flooding
• Strong Winds/Squall


  Cyclones cause severe damage to infrastructure through high speed winds, very strong winds damage installations, dwellings, communications systems, trees etc., resulting in loss of life and property, gusts are short but rapid bursts in wind speed, squalls are longer periods of increased wind speed and are generally associated with the bands of thunderstorms that make up the spiral bands around the cyclone
• Torrential rains and inland flooding


  Torrential rainfall (more than 30cm /hour) associated with cyclones is another major cause of damages, unabated rain gives rise to unprecedented floods, rain water on top of the storm surge may add to the fury of the storm, rain is a serious problem for the people who become shelter less due to cyclone, heavy rainfall from a cyclone is usually spread over a wide area and cause large scale soil erosion and weakening of embankments
• Flood


  An excess of water (or mud) on land that's normally dry, caused by high flow, or overflow of water in an established watercourse, such as a river, stream, or drainage ditch; or ponding of water at or near the point where it rained, a duration type event, can strike anywhere without warning, occurs when a large volume of rain falls within a short time
• Types of Floods

  • Flash Floods
  • River Floods
  • Coastal Floods
  • Urban Flood
  • Ice Jam
  • Glacial Lake Outbursts Flood (GLOF)
• Flash Floods


  Floods occurring within six hours, mainly due to heavy rainfall associated with towering cumulus clouds, thunderstorms, tropical cyclones or during passage of cold weather fronts, or by dam failure or other river obstruction, requires a rapid localized warning system, caused by the saturation of soil that has low absorption in some places and areas, common places are areas near dams, deforested areas, and places at the foot of mountains and hills
• River Floods


  Floods caused by precipitation over a large catchment's area, melting of snow or both, build up slowly or on a regular basis, may continue for days or weeks, major factors are moisture, vegetation cover, depth of snow, size of the catchment's basin
• Coastal Floods


  Floods associated with cyclonic activities like Hurricanes, Tropical cyclones, etc. generating a catastrophic flood from rainwater which often aggravate wind- induced storm and water surges along the coast
• Urban Flood


  As land is converted from agricultural fields or woodlands to roads and parking lots, it loses its ability to absorb rainfall, urbanization decreases the ability to absorb water 2 to 6 times over what would occur on natural terrain, during periods of urban flooding, streets can become swift moving rivers, while basements can become death traps as they fill with water
• Ice Jam


  Floating ice can accumulate at a natural or man-made obstruction and stop the flow of water thereby causing floods, flooding can also occur when the snow melts at a very fast rate
• Glacial Lake Outbursts Flood (GLOF)


  Many of the big glaciers which have melted rapidly and gave birth to the origin of a large number of glacier lakes, due to the faster rate of ice and snow melting, possibly caused by the global warming, the accumulation of water in these lakes has been increasing rapidly and resulting to sudden discharge of large volumes of water and debris and causing flooding in the downstream
• Characteristics of flood

  • Depth of water
  • Duration
  • Velocity
  • Frequency of occurrence
  • Seasonality
• Drought


  A temporary aberration unlike aridity, which is a permanent feature of climate, seasonal aridity (ie. a well-defined dry season) also needs to be distinguished from drought, a normal, recurrent feature of climate and occurs in all climatic regimes and is usually characterized in terms of its spatial externsion, intensity and duration, conditions of drought appear when the rainfall is deficient in relation to the statistical multi-year average for a region, over an extended period of a season or year, or even more, differs from other natural hazards in that there is no universal definition, being of slow-onset it is difficult to determine the beginning and end of the event, duration may range from months to years and the core area or epicentre changes over time, no single indicator or index can identify precisely the onset and severity of the event and its potential impacts, multiple indicators are more effective, spatial extent is usually much greater than that for other natural hazards, making assessment and response actions difficult, since impacts are spread over larger geographical areas, impacts are generally non-structural and difficult to quantify
• El Niño


  Warming phase of the El Niño Southern Oscillation, when warm waters in the western Pacific Ocean move to the east along the equator