Disaster Basics and Risk Factors

Disaster Basics

• A disaster is an event that happens suddenly and disrupts normal life patterns
• Natural disasters originate from atmospheric, geological, and hydrological events
• Man-made disasters are caused by human intent, negligence, or error

Risk Factors Underlying Disasters

• Housing and building development that disregards environmental impact increases disaster risk
• Physical structures in disaster-prone areas are at greater risk
• Institutional frameworks and systems are crucial for risk reduction and prevention

Effects of Disasters

• Primary effects are direct consequences, such as flooding and destruction
• Secondary effects result from primary ones, like disruption of utilities
• Tertiary effects are long-term impacts, such as trauma and depression

Measuring Disaster Severity

• Severity is measured by the number of human lives missing or lost

Components Affected by Disasters

• People are assessed based on casualties, missing persons, and injuries
• Buildings and infrastructure suffer destruction or damage
• Economies are affected through business, transportation, and communication losses
• The environment experiences negative impacts on air, soil, water, and ecosystems

Perspectives on Disaster

• Perspective is one's attitude or way of regarding a disaster
• Physical perspective involves visible damages
• Psychological perspective focuses on emotional and cognitive reactions
• Sociocultural perspective deals with community responses, customs, and beliefs
• Economic perspective relates to disruption of economic activities
• Political perspective concerns government services for damage reduction
• Biological perspective looks at injuries and susceptibility to infections

Vulnerability Defined

• Vulnerability is the diminished capacity to cope with hazards
• Situation-specific vulnerability depends on regional factors
• Hazard-specific vulnerability varies based on the type of threat

Factors to Assess Vulnerability

• Proximity to a hazard event increases vulnerability
• Population density is a key consideration
• Capacity and efficiency to reduce disaster risk make a community less vulnerable
• Building codes and disaster policies can reduce vulnerability
• Exposure refers to at-risk elements

Hazards

• Physical hazards can harm the body, e.g., vibration and noise
• Cultural/social hazards include location and socioeconomic status
• Economic hazards are major events that cause short-run economic impacts
• Environmental hazards threaten the surrounding environment

Sectors Vulnerable to Hazards

• Agriculture and food supplies
• Watersheds, forestry, biodiversity, and water resources

Exposure and Vulnerability in the Philippines

• Most cities exposed to natural hazards are in the Philippines
• The Philippines experiences around 20 typhoons annually

World Cities at Risk

• Port Villa (Vanuatu)
• Tuguegarao (Cagayan)
• Lucena (Quezon)
• Manila
• San Fernando (Pampanga)
• Cabanatuan (Nueva Ecija)
• Batangas
• Taipei
• San Carlos (Pangasinan)
• Naga (Camarines Sur)

Hazards Defined

• Hazards have the capacity to damage lives, properties, and the environment

Types of Hazards

• Natural hazards are natural phenomena that pose threats
• Human-made hazards include civil conflict and environmental degradation
• Safety hazards cause immediate injuries
• Chemical hazards include gases and liquids that cause harm
• Biological hazards are living organisms that cause infectious diseases
• Physical hazards can injure without contact
• Ergonomic hazards result from repetitive work
• Psychosocial hazards affect mental health

Long-Term Impacts of Natural Hazards

• Physical
• Psychological
• Sociocultural
• Economic
• Environmental
• Biological

Understanding Earthquakes

• Earthquakes are caused by energy release in the Earth's crust
• The focus/hypocenter is where the break occurs underground
• The epicenter is above the focus on the surface
• Seismic waves are energy released during an earthquake

Types of Seismic Waves

• Body waves travel through the Earth's interior
• Surface waves travel on the Earth's surface

Types of Body Waves

• Primary waves travel through all states of matter and are the first to be detected
• Secondary waves cannot pass through liquids

Types of Surface Waves

• Love waves move side-to-side
• Rayleigh waves move up and down

Inge Lehmann

• Inge Lehmann discovered the inner core with a type of seismic wave called primary wave

Instrumentation

• Seismographs are devices used to detect seismic waves
• Seismometers are sensors in seismographs
• Seismograms are records of earthquakes

Elastic Rebound Theory

• Harry Fielding Reid contributed to the elastic rebound theory
• The Elastic Rebound Theory describes how energy is released in an earthquake

Earthquake Hazards

• Ground shaking is sideways and up and down motion felt during an earthquake
• Ground rupture is the fracture and displacement of the Earth's surface
• Liquefaction occurs when the ground loses strength due to shaking
• Landslides involve the movement of rock or debris down a slope
• Tsunamis are catastrophic waves caused by water displacement
• Induced ground subsidence is the lowering of ground due to earthquakes

Tsunami Warning Signs

• Offshore earthquake
• Rise or fall of coastal waters
• Exposure of corals
• Sound of approaching train
• Animal behavior
• Drawback

Earthquake Preparedness

• "Drop, Cover, and Hold On" reduces the chance of injury

Volcano Hazards

• Volcano hazards are potentially dangerous volcanic processes Volcanoes are openings in the Earth’s crust

Volcano Statistics

• There are more than 1,500 active volcanoes worldwide
• Mt. Olympus located on Mars is the tallest volcano
• Volcano is named for Vulcan, the Roman god of fire
• Mauna Loa in Hawaii is the largest active volcano

Volcano-Related Hazards

• Lahars are mixtures of water, pyroclastic materials, and rock fragments
• Ashfall consists of pulverized rock, minerals, and volcanic glass
• Ballistic projectiles are rock fragments ejected from a volcano
• Volcanic gases contain sulfur dioxide and hydrogen sulfide, which are poisonous
• Lava flows are molten rock that pours down slopes

Types of Ballistic Projectiles

• Projectile of rock or fragment is solid
• Launched in partially molten or molten state

Monitoring Volcanoes

• Changes in ground deformation, gas emissions, and temperature can indicate an eruption

Signs of Impending Volcanic Eruption

• Increased tremors or small earthquakes can precede eruption

Rainfall Induced Hazards

• Rainfall Induced Hazards are common on terrain with steep topography and soils that have degradable strength/
• Transform into debris flow

Landslides

• Landslides involve ground movement on sloping terrain
• Landslides are a natural agent for erosion

Sinkholes

• Sinkholes are holes in the ground that resulted from collapse of the surface
• Sinkholes Occur in areas where soil foundation is made of soft minerals like limestone, saltbeds, or acidic rocks.

Assessing Landslides And Sinkholes

• Abney level or laser range finder measures slope angles
• Ground Penetrating Radar can detect objects and cracks under the soil