Natural Hazards, Mitigation and Adaptation Caused by : Geologic Processes, Hydrometeorological Phenomena and Coastal Processes

1. Natural Hazards, Mitigation, and Adaptation
 Events that occur as part of the natural cycles of earth and may cause potential damage to a community.
 An event that causes widespread losses (human, economic, and environmental) and disrupts the normal
functioning of a community is called a disaster
 Vulnerability- defined by the UN Office for Disaster Risk Reduction
 it refers to the “characteristics and circumstances of a community, a system, or asset that make it susceptible to
the damaging effects of a hazard.”
Climate Change
 A key driver of increasing hydrometeorological disasters, especially global warming and sea level rise.
 A challenge to humankind.
 Flooding is a global concern & increasing in its intensity. It is forecasted that temperature increase of 3-4oC could
result in displacement of nearly 330 million people only through flooding.
 A 1 metre sea level rise would make at least 56 million people environmental refugees in the developing world.
Some Climate Change Impacts (IPCC)
In 2100 : half of the world’s population will sufffer from water stress
Subtropical zones: Less precipitation and increased desertification
Tropical zones: Increased health risks
High latitudes: permafrost decrease
Coastal zones: coastal erosion; storm surges; salt water intrusions
Cost of global warming in 2050: 300 billion USD per year
Hazards Caused by Geologic Processes
1. Earthquakes- this are the vibrations of the Earth caused by rapid release of energy.
List of Active Fault
* Marikina Valley Fault :
Montalban San Pedro
Biñan San Mateo
Carmona Marikina
Santa Rosa Pasig
Calamba Taguig
Tagaytay Muntinlupa
Oriental Mindoro
• FOCUS = place deep within the Earth and along the fault where rupture occurs
• EPICENTER = geographic point on surface directly above focus
• SEISMIC WAVES = produced by the release of energy
– move out in circles from the point of rupture (focus)
– 2 types: surface & body (travel inside & through earth’s layers)
• P waves: back and forth movement of rock; travel thru solid, liquid, gas
• S waves: sideways movement of rock; travel thru solids only
• Seismographs record earthquake waves
• Richter scale = measurement of energy released based upon wave amplitude (size of vibration)

2. a) Ground Shaking- the vibration of the ground due to plate movement or seismic waves during an earthquake.
b) Surface faulting- the tearing of the ground when the movement of a fault deep within Earth breaks through to ground
surface.
c) Tsunamis- very high, large waves or seismic sea waves caused by the sudden movement of the ocean floor due to
earthquakes, volcanic eruptions, man-made explosions, and on some occasions, landslides.
2. Volcanic Eruptions
The location of the Philippines in the Pacific Ring of Fire is near the subduction zone ofthe Pacific Plate. It may be followed
by other related hazards such as lahar flow, ash fall, pyroclastic flow, ballistic projectiles, emission of volcanic gases and
lava flow.
3. Landslides
Landslide occurs in sloping terrain. Usually, if the soil is not compact and devoid of vegetation, gravity can drive soil and
rocks to slide. Landslide can be triggered by wind, water, rainfall or earthquake.
a) Rainfall-induced landslides – In sloping areas, the gravitational descentofloosened soil makes it possible for landslides
to occur. This is a common phenomenon in places with tropical climates after very intense and long rains during the wet
season.
b) Earthquake-induced landslides – This type of landslide happens during or after an earthquake when a piece weakened
landslides off primarily due to gravity. This may be due the natural makeup of the soil consisting of a softer layer beneath
solid bedrock, man-made activities that induce erosion such as deforestation, excavation, mining and quarrying, or thunder
and other vibrations from natural ground activities.
Hazards Caused by Hydrometeorological Phenomena
1. Tropical Cyclones
Also known as typhoons for those occurring in the Northwest Pacific and hurricanes for those developing in the Atlantic
and Northeast Pacific are storm systems characterized by rapidly spiraling storms, low pressure center, and intensely strong
winds.
a) Strong winds- the strength of winds can destroy lightweight structures and uproot plants and trees.
b) Heavy rainfall leading to flooding- some typhoons are associated with continuous and heavy rains.
2. Monsoons - seasonal winds. The Philippines experiences two monsoons every year the Amihan and the Habagat.
Amihan- northeast monsoon is characterized by cold gusty wind with little or no precipitation. Blows to the east.
Habagat- southwestmonsoon is characterized by hotand humid atmosphere with frequent heavy rainfall. Blows to the west.
3. Tornadoes - A tornado or locally known as ipo-ipo is a rapidly swirling condensation funnel whose narrow end comes in
contact with the ground.
Hazard Caused by Coastal Processes
Coastal Erosion- the seawater through wave actions, tidal currents, strong winds, or a combination of all of these loosens
the soil on the shore, which eventually destroys the integrity of land.
Submersion- As global atmospheric temperatures rise, oceans and seas become warm and expand. Rising global
temperatures also speed the melting of glaciers and ice caps.
Storm Surges- may occur in coastal areas when typhoons make landfall. The strong winds of the cyclone push the waters
toward the shore, sometimes generating huge waves capable of destroying sea walls and structures facing the sea.
Saltwater Intrusion- the movement of minerals and salts from coastal seas to freshwater aquifers.