Disaster Risk & Reduction 1st Periodical

Disaster

serious disruption occurring over a short or long period causing loss that exceeds the affected community to cope

• Natural Disaster

• Man-made Disaster

Classification of Disasters

Hazard

• potential destructive event or human activity

• may be active or dormant, be it single, sequential or both

• Identified by its location, probability & frequency of occurrence

Vulnerability

• lack of capacity to flee from hazard exposure

• Determined by physical, social, economic, & environmental factors

• characteristics or circumstances of a asset to make it susceptible to damaging effects

Exposure

• situation of elements at risk ie. people, infrastracture, housing, production capacities, and other tangible exposed

• does not determine risk alone

Capacity

factors that help a community reduce its vulnerabilities, prevent risks & recover

Risk

• combination of Hazard & vulnerability & exposure

• probability of detrimental effects

Disaster Risk

combination of severity and frequency of a hazard, numbers of people and elements exposed to the hazard and vulnerability to damage

• Climate Change

• Globalized Economic Development

• Poorly Planned & Managed Urban Development

• Environmental Degradation

• Poverty & Inequality

• Weak Governance

Risk Factors Underlying Disaster

• Physical

• Psychological

• Socio-cultural

• Economic

• Political

• Biological

Different Perspective of Disaster

Physical Perspective

cause great physical damage in a community, lives, physical disabilities, & property damage

Psychological Perspective

suffer from mental illness like PTSD

Socio-cultural Perspective

Change in individual roles or disruption of social relationships

Economic Perspective

Affect the economic condition leading to unemployment, loss of food, public infrastructure

Political Perspective

emphasized the role of political leaderships and decision-making in addressing & mitigating the impact

Biological Perspective

Effects by a prevalent kind of disease in an epidemic & pandemic level

• Physical

• Social

• Economic

• Environmental

Types of Vulnerabilities

Physical Vulnerability

• determined such as population density, remoteness of settlement, site, design & mats

Social Vulnerabilities

• inability of people to withstand the impacts due to social interactions

• literacy & education, peace & security, and access to human rights

Economic Vulnerability

low-income community are more susceptible due to lack of resources & other measures

Environmental Vulnerability

key aspect of natural resources depletion & degradation

• Demographic Factors

• Socio-Economic Factors

• Community Preparedness

• Dealing with the After-Effects

Factors why Sectors of Society are more Vulnerability than others

• Population density

• Age of population

• Distribution of population

Demographic Factors

• Building codes

• Scientific monitoring & Early warning system

• Communication Networks

• Emergency Planning

Community Preparedness

• Wealth

• Education

• Nature of Society

• Understanding of the Area

Socio-Economic Factors

• Insurance Cover

• Emergency Personnel

• Aid Request

Dealing with the After-Effects

• Geophysical

• Hydrological

• Meteorological

• Climatological

• Biological

• Human Beings

Classifications of the Naturally Hazard

Geophysical Hazards

• volcanoes, earthquakes, tsunamis, dry landslides

Hydrological Hazards

• wet landslide, floods, inundations

Meteorological Hazards

• storms, hurricanes, cyclones, excessive rain, typhoons

Climatological hazards

• droughts, extreme temperature, fires, healt/cold waves

Biological Agents

• Insect infestations, epidemics, animal stampedes

Human Beings

• chemical, nuclear, industrial, technological hazards

Geological Hazards

crust of the earth that pose a threat
Earthquakes, Volcanic eruption, Landslide

Hydro-metereological

Extreme meteorological & climate events
Typhoon, Thunderstorm, storm surge

Atmospheric

interfere with the body’s ability to transport & utilze oxygen
tropical cyclones, tornadoes

Catastrophic

events that cause widespread loss of life or harm, resulting in major reputation or damage
Volcanic Eruption, disease outbreaks

Rapid Onset

Quickly & with little warning

Slow onset

Slow and may take years to develop

1. Primary Effects

2. Secondary Effects

3. Tertiary Effects

Types of Effects of Hazards

Primary Effects

• result of the process itself;

• Ground Shaking, thunders, High sea waves

Secondary Effects

• because of primary effect caused

•  fire ignited as a result of earthquake, disruption of electrical power and water service as a result of earthquake, flood or flooding caused by landslide

Tertiary Effect

• long term effects set off as a result of the event

• Ground Shaking

• Faulting & Ground Rupture

• Liquefaction

• Ground Displacement

Earthquake Hazards

Ground Shaking

• main hazard effect, vibration of the ground

Faulting & Ground Rupture

occurs on fault zones, primary effect

Liquefaction

mixing of soil & groundwater becoming soft and acts like quicksand

Ground Displacement

secondary/Tertiary caused by faulting

uplift and subsidence of the land surface

Fault

fracture/crack where two rock blocks or slide past one another

• Normal

• Reverse

• Strike-&-slip

• Oblique

Types of Fault

Normal

block above the fault has moved downward relative to the block below; occurs in extension

Reverse Fault

• Block has moved upward relative to the block

• Common in compression area

• Thrust fault

Strike-slip fault

two sides passed horizontally past each other

Oblique

fault plane is at an angle but motion is both horizontal & vertical

Divergent Boundaries

• two plates slide apart

• rift valleys, , underwater mountains, mid-oceanic ridges

Convergent Boundaries

• plates collide with one another

• Mounatains, volcanoes, subduction zones, deep sea trenches

Transform Boundaries

• move sideways

• fault line, ridges, valleys, earthquakes

Volcanic Earthquakes

• Volcano-Tectonic Earthquakes

• produced by stress changes in solid rock to injection of magma

Directed Blast

• depressurization triggered by landslide on north flank of the volcano

• 19 miles, affected area

Tephra

• rock fragments

• Blocks & Bombs - large pieces (64 mm)

Volcanic Gases

• Acid rain, Produced when high concentrations of gases are leeched out of the atmosphere

• Some form salts and aerosols

• Escape from pyroclastic flows, lahars, & lava flows

Lava Flows

• least hazardous, speed depends on temperature, silica content, extrusion rate and slope of the land

Debris Avalanches

• unstable slope collapses and debris is transported away from the slope

Pyroclastic Surge

• low density flows of pyroclastic material

• lack concentration of particles & has lots of gases

• travel up 10km; turbulent & fast

Pyroclsatic Flow

• fluidized masses of rock fragments & gases

• Form when
  -eruption column collapses
  -result of gravitational collapse or explosion on lava dome

Lahars

• similar to pyroclastic flow but more water

• Form when debris contain water from snow & ice, when released mixed with loose debris

• Fertile Soil

• Valuable Minerals

• Water Reservoir

• Geothermal Resources

• Scenic Beauty

Benefits of Volcanoes

Taal

smallest volcano; Batangas

Mt. Pinatubo

2nd largest eruption of 20th century; Zambales

Mayon

world’s most perfectly shaped cone; Albay

Mt.Hibok-Hibok

Stratovolcano on Camiguin Island

Mt . Apo

Large solfataric, dormant stratovolcano of Mindanao

Rotational Landslide

ground rotates & slides along a curved failure plane

Translational Landslide

Ground slides with little rotation along a flat plane parallel to the surface

Block Slide Landslide

Translational type; one block of surface material that moves

Rockfall Landslide

gravity sends rocks & other mats in a downslope

Topple

Pieces of a cliff or rock face fall forward as large block

Earthflow

fine-grained mats liquefies and runs in hourglass shape

Lateral Spread Landslide

• surface material extends or spread on gentle slopes; associated with earthquake shaking

Debris Flow Landslide

rapidly moving of water, mud, trees, and other that flows down valley

Debris Avalanche Landslide

large & fast moving debris flow

Creep Landslide

soil & surface material slowly moves down

• Natural Landslide

• Anthropogenic Factors

Types of Landslides

Sinkhole

• cenote, sink, swallet, swallow hole, doline

• cause by collapse

Karst Processes

Chemical Dissolution of carbonate rocks or suffusion

• Cover-collapsed

• Cover-subsidence

Types of Sinkholes

Cover-collapsed

develop quick & cause catastrophic damage

Cover-subsidence

Overtime with ground subsiding gradually