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• Other geological Hazards


  • Bolide impact
  • Ground Subsidence
  • Coastal Erosion
• Geological Hazard


  • Is an adverse geologic condition capable of causing damage or loss of property or life
  • These geologic processes only become hazards when humans get in their way; if there were no people affected, we would find these natural phenomena interesting, but not concerning
• Ground Subsidence


  The lowering of the Earth's surface usually with respect to the mean sea level
• Causes of Ground Subsidence


  • Carbonate dissolution and collapse
  • Excessive groundwater withdrawal
  • Extraction of oil and natural gas
  • Earthquakes
  • Underground mining methods
  • Isostatic rebound
  • Change of Season
• Carbonate dissolution and collapse


  • Abundance of limestone terrains due to its geographic setting and extensive coastlines
• Excessive groundwater withdrawal


  • Pressure of fluids filling up voids in permeable sedimentary rocks supports the overlying rock layers and the ground surface
• Extraction of oil and natural gas


  • Withdrawal of fluids is mainly anthropogenic but can also be caused by natural processes such as outflow through spring
• Earthquakes


  • Subsidence may occur during liquefaction, which takes place in areas with fine-grained sediments or in areas that were reclaimed
• Underground mining methods


  • Cause the collapse of the surface in which the appearance, amount and areal dimensions can be predicted
  • Occur unexpectedly in abandoned old portions of mines

  
• Isostatic rebound


  • The Earth's crust, reacts to the additional or removal of load on its surface
  • If a large mass is removed through weathering and erosion or melting of large ice sheet glaciers, uplift takes place
  • Areas receive large deposits of sediments like valleys and bodies of water tend to become even lower in elevation because of isostatic subsidence

  
• Change of Season


  • Wet season - clays in the soil tend to expand
  • Dry season - shrink again
• Mitigating Subsidence-Related hazards


  1. Map out the areas which are subsidence-prone and to either avoid development in the area or adapt by modifying or strengthening structures

  2. Structures and roads can be elevated

  3. Dikes and pumping or drainage systems can also be constructed
• Coastal Erosion


  • The gradual wearing away or loss of land, beaches, dunes, or cliffs along a coastline due to natural processes such as waves, currents, tides, and wind, as well as human activities
  • Coastal erosion is a natural phenomenon that occurs over time, but it can be accelerated or exacerbated by human interventions and climate change
• Causes of Coastal Erosion


  • The sediments redistribution process that moves, water, sand, and bigger rock fragments also involves currents, tides, wind-driven water, ice, rainwater, and groundwater
• Human Activities that can accelerate coastal erosion process


  • Removal of vegetation cover exposing sediments to wind and water action
  • Concentration of drainage water flow into the sea, causing erosion of the coast
  • Construction of structures that interfere with the natural flow of coastal materials, causing erosion in adjacent areas of the shore
  • Building activities that damage natural protective features
  • Activities which destroy natural protective features such as dunes and vegetation cover
  • Shipping and boating activities producing extra wave action
• Managing Coastal Erosion


  1. Coastal erosion can be quite challenging to manage

  2. We should not hastily attempt to build structures , like seawalls to stabilize shoreline

  3. Land-use management and planning should always be the best option

  4. Prohibiting construction in areas of active coastal erosion

  5. Restricting development of public utilities