L9 | NATURAL HAZARDS

• NATURAL HAZARDS

  • Events that occur as a part of the natural cycles of Earth and may cause damage to a community.
• DISASTER

  • disruption of the normal functioning of a community
• VULNERABILITY

  • Defines by the United Nations Office of Disaster Risk Reduction
  • characteristic and circumstances of a community, system, or asset that make of it susceptible to the damaging effects of a hazard
• HAZARDS CAUSED BY THE 3 GEOLOGIC PROCESSES:

  1. EARTHQUAKES
  2. VOLCANIC ERUPTIONS
  3. LANDSLIDES
• EARTHQUAKES

  1. GROUND SHAKING
  2. SURFACE FAULTING
  3. TSUNAMIS
• GROUND SHAKING

  • ground motion
  • a principal cause of the partial or total collapse of structures,
  • vibration of the ground caused by seismic waves during an earthquake
• SURFACE FAULTING

  • offset or tearing of the ground surface by differential movement along a fault during an earthquake.
• TSUNAMIS

  • Very high, large waves or seismic sea waves caused by the sudden movement of the ocean floor
• VOLCANIC ERUPTIONS

  1. LAHARS AND FLOODS
  2. LAVA FLOWS AND DOMES
• LAHARS AND FLOODS

  • lahar (or mudflow) is a flowing slurry of volcanic debris and water that originates on a volcano. 
• LAVA FLOWS AND DOMES

  • Fluid lava forms long thin flows on slopes and flat-topped lava lakes in flat areas and topographic depressions, while viscous lava forms short stubby flows on slopes and steep sided domes around their vents. 
  • In either case lava flows seldom threaten human life because they move slowly and their path can be predicted.
• LANDSLIDES

  • Occur in a sloping terrain. 
  • can be triggered by rainfall or earthquake.
• LANDSLIDES

  1. RAINFALL INDUCED
  2. EARTHQUAKE INDUCED
• RAINFALL-INDUCED

  • caused by heavy rains that can loosen soil and makes the foundations of the structures weak
• EARTHQUAKE-INDUCED

  • Occurs during or after an earthquake due to gravity.
• EARTHQUAKE

  • either a natural occurrence or man-made.
• MANAGING LANDSLIDES

  • Plant more trees. 
  • Build channels for diversion of mudflow 
  • Put together an emergency supply kit. 
  • Put important things on containers etc. preventing ashfall.
• IF LANDSLIDES OCCUR WITHOUT WARNING

  • Stay alert 
  • Be attentive 
  • Stay away from lower elevations or paths of debris 
  • take shelter under a sturdy table or structure.
• ITCZ

  • Intertropical Convergence Zone
  • area that encircles the Earth near the equator where trade winds meet.
• PAGASA

  • Philippine Atmospheric, Geophysical and Astronomical Services and Administration
  • government agency that provides information on meteorological, astronomical and climatological activities in the Philippine territory.
• HAZARDS CAUSED BY HYDROMETEOROLOGICAL PHENOMENA:

  1. TROPICAL CYCLONES
  2. MONSOONS
  3. TORNADO
• TROPICAL CYCLONES

  • Typhoons (Northwest Pacific) or hurricanes (Atlantic and Northeast region) are storm systems characterized by rapid spiraling storms, low-pressure center, and intensely strong winds. 
• MONSOONS

  • seasonal winds. 
• 2 TYPES OF MONSOONS IN THE PH:

  1. AMIHAN
  2. HABAGAT
• AMIHAN

  • The northeast monsoon is characterized by cold gusty winds with little precipitation. 
  • Begins in early September - May or June. Winds blow in the east.
• HABAGAT

  • The southwest monsoon is characterized by a hot and humid atmosphere with frequent or heavy rainfall. 
  • Begins in June and Ends in August or September. Winds blow in the west
• TORNADO

  • Locally known as ipo-ipo. 
  • rapidly swirling condensation funnel whose narrow end comes in contact with the ground.
  • usually carries debris and other objects that can be picked up from the ground. 
• TORNADO

  • occur anywhere in an average number of 12-24 times a year.
  • Characterized by:
  • Storm
  • Debris
  • Fire
• COASTAL AREAS

  • transition places between land and sea. 
  • areas are considered low-lying. 
  • very dynamic, 
  • it interacts with all natural systems and processes that happen on land, in the marine environment and in the atmosphere.
• COASTAL COMMON HAZARD

  1. COASTAL EROSION
  2. SUBMERSION
  3. STORM SURGES
  4. SALTWATER INTRUSION
• COASTAL EROSION

  • wearing away of land and the removal of beach or dune sediments by wave action, tidal currents, wave currents, drainage or high winds (see also beach evolution).
• SUBMERSION

  • sustainable cyclic portion of coastal erosion where coastal sediments move from the visible portion of a beach to the submerged near shore region, and later return to the original visible portion of the beach. 
  • The recovery portion of the sustainable cycle of sediment behaviour is (accretion).
• STORM SURGES

  • rise in sea level that occurs during tropical cyclones, intense storms also known as typhoons or hurricanes. 
• SALTWATER INTRUSION

  • movement of saline water into freshwater aquifers
  • occurs naturally to some degree in most coastal aquifers, owing to the hydraulic connection between groundwater and seawater.
• PREVENTION AND MANAGEMENT OF MARINE AND COASTAL HAZARDS

  • Prepare an emergency survival kit.
  • Create an evacuation plan. 
  • Know where the evacuation center is and how to get there. 
  • Listen to news from any means.