DRRR 4th monthly test

• Two types of disaster

  1. Natural
  2. man-made
• Natural disaster

  -       Strikes without warning

  -       though most areas know what is "normal" for their areas and prepare for such occurrences. Assessing is done by reviewing the history of the region, looking at what weather and other disasters have occurred in the past.
• Man-Made disasters

  There are some man-made disasters that occur or can occur with some warning, such as knowing that a dam is weak and, without proper mitigation, it will break, releasing a flood. However, most of the serious man-made disasters are the result of unexpected accidents (e.g., an oil tanker running aground or a power plant blowing up) or deliberate acts of terrorism.
• Man-made disasters

  • There are also epidemics and pandemics that occur with some regularity and, while one may not consider these man-made, many are the result of people living with livestock, as in influenza, or living in crowded conditions, which helps spread tuberculosis.
• Aspects of disasters

  • Physical and environmental
  • Socio-economic
  • Educational
  • Biological
  • Political
• 1.    Physical and environmental

  a.    When a disaster hits, the first line of impact is the environment. Disaster causes drastic changes in the structure of the environment
• 1.    Socio-economic

  Impacts of disaster in the socio-economic aspect include the state of the social well-being and the financial resources of the community
• 1.    Educational

  Access to information is important in reducing the hazardous effects of disasters. Observation and data analysis are not just essential for identifying risk in disasters but also to educate and train people on how to reduce disaster risk.
• 1.    Biological

  • Disasters can cause health problems to individuals. On a larger scale, these diseases can cause an epidemic or an outbreak especially if emergency care is not available.
  • a.    In terms of biological diversity, animals, and plants that live in a community where disaster strikes can drastically decrease in number. This would result in imbalance in the ecosystem and potentially limited access to food resources, agriculture, and livestock.
• 1.    Political

  • A disaster may also change the way citizens feel about other people in general, like after giving donations to assist affected individuals. A disaster may also affect public opinion about the government, because citizens can feel and see how the government handled the effects of disaster.
• Effects of disaster

  • Population
  • Food
  • Health
  • Psychological
• 1.    Population

  a.    Increased population in evacuation centers is the most immediate effect during a disaster. Natural disasters such as earthquakes and typhoons force people to vacate their homes and seek shelter to a nearby safe area.
• 1.    Food

  • Food becomes limited after an occurrence of disaster. Sources of food from farms, poultry, and aquaculture become damaged after a disaster, thus the supply of food becomes limited.
• 1.    Health

  a.    One consequence of disaster is threat to the population’s health. Severe flooding caused by typhoons can increase the presence of stagnant water in the area. This stagnant water is a perfect breeding ground for mosquitoes to lay their eggs and for the growth of bacteria.
• 1.    Psychological

  1. The devastating impacts of disaster can be traumatic for any person who has experienced it. Exposure to deaths and catastrophe can be unforgettable to anyone, especially to children. Many children could develop Post-traumatic Stress Disorder (PTSD) after experiencing such disastrous events. PTSD is a serious psychological condition from extreme trauma. Inability to notice and address it early, can lead to a lifetime of emotional distress and psychological damage.
• Factors affecting Severity of effects

  • Severity of Exposure
  • Age
• § Severity of Exposure - A person exposed to a more severe disaster has higher risk for mental distress. For example, a family who experienced a first-hand fire incident has a higher risk than their friends and other people who have watched the news about the fire. Psychological problems after disasters are usually triggered by exposure to the death of an immediate family member.
• Age - Research shows that individuals ranging from 40-60 years old are more prone to disaster distress than children. Adults have more pressures like their jobs and families, and these adds up to their emotional distress after a disaster. The higher stress of parents is related to their children’s slow recovery
• Human Resilience

  Humans are naturally resilient. Resilience is the ability of individuals to recover from the impacts of a disaster. There are several factors that increase the resilience of an individual:

  1. Social Support
  2. Coping confidence
• Social support ​includes emotional support by sharing traumatic experiences, coping mechanisms, and finding a sense of comfort from others.
• Coping confidence ​is the self-efficiency to believe that one can survive any disaster and reduce mental distress in the future. This method of coping includes values like optimism, hope, and confidence.
• Intensity

  -       Strength and power of an earthquake to which we can predict the level of destruction
• Magnitude

  -       Measures the severity of an earthquake

  -       Stays the same
• Earthquake Hazard

  -       The perceptible shaking of the surface of the Earth, resulting from the sudden release of energy in the Earth’s crust that creates seismic waves (comes from the mantle)
• Hypocenter : origin of the Earthquake beneath the surface
• • Epicenter: origin of the Earthquake on the surface level
• Types of natural earthquake

  1. Tectonic
  2. Volcanic
• 1.    Tectonic

  a.    Sudden movements around faults and plate boundaries
• 1.    Volcanic

  a.    Produced by movement of magma beneath volcanoes
• Earthquake hazards

  1. Ground shaking/vibration
  2. Earthquake vibrations
  3. Ground rupture
  4. Liquefication
  5. Earthquake induced landslide
  6. Tsunami
  7. Earthquake induced ground subsidence and lateral spreading
• 1.    Ground shaking/Vibration

  a.    Refers to the disruptive up, down, and sideways motion experienced during an earthquake.
• Earthquake vibrations

  -       Caused by sudden slippage along fault zone

  -       Fault: a fracture on which one body of rock slides past another
• Ground Rupture

  o   An offset of the ground surface when fault rupture extends to the Earth’s surface

  o   Surface rupture is an offset of the ground surface when fault rupture extends to the Earth’s surface. Any structure built across the fault is at risk of being torn apart as the two sides of the fault slip past each other.
• Ground rupture

  • Normal – and reverse – (collectively called dip – slip) faulting surface ruptures feature vertical offsets while strike – slip faulting produces lateral offsets. Many earthquake surface ruptures are combinations of both. Structures that span a surface fault are likely to suffer great damage surface ruptures.

  Causes:

  • The lithosphere breaks when its strength is overcome by the large amount of stress applied
  • Rock failure that involves the slipping of lithosphere blocks past each other is called faulting
• Liquefication

  o   Takes place when loosely packed water-logged sediments at or near the ground surface lose their strength in response to strong ground-shaking

  o   Water will be mixed with soil, it will be like quicksand
• Liquefication

  • The shaking caused by the passing of seismic waves, causes loss of equilibrium or disturbance of the granular structure
  • The results in increased pore pressure because it always moves between grains. Once pressure exceeds the weight of overlying material, water is released and causes the sediment grains to separate as they are pushed apart.
• Liquefication

  • a phenomenon in which the strength and stiffness of a soil is reduced by earthquake shaking or other rapid loading. It normally occurs in saturated soils, that is, soils in which the space between the individual particles is completely filled with water.
  • Prior to an earthquake, the water pressure is relatively low – the weight of the buried soil rests on the framework of grain contacts that comprise it.
• Liquefication

  • earthquake shaking can disrupt the structure, the soil particles no longer support and all the weight, and the groundwater pressure begins to rise.
• Earthquake induced landslide

  • Ground shaking greatly increases the likelihood of landslides where landscape is susceptible to these type of ground
  •  Landslides are frequently triggered by strong ground motions. They are important secondary earthquake hazards.
• Earthquake induced landslide

  • The term landslide includes a wide range of ground movement, such as rock falls, deep failure of slopes, and shallow debris flows. However, gravity acting on a steep slope is the primary reason for all landslides.
  • Strong earthquake- induced ground shaking greatly increases the likelihood of landslides where landscape is susceptible to these types of ground failure.