DRRR MIDTERMS

When does a natural event become a hazard?

When it has a potential to harm lives in large quantity

When does a hazard become a disaster?

When a destructive agent hazard hits a vulnerable populated area

Vulnerability

the degree of loss or the human dimension of disasters and is the result of the range of economic, social, cultural, political effects that shape people's life

Disaster

Hazard x Vulnerable Population

Disaster Risk

potential loss of life, injury, or destroyed/damaged property

Disaster Risk

Hazard x Exposure x Vulnerable Population

severity of event, quantity of exposure, vulnerability level

magnitude of disaster depends on:

True

Disasters are inherently unexpected or have little to no warning

False

Disaster can be managed through normal means

True

Disaster knows no political boundary

False

Disasters doesn't expose lack of disaster planning

Disaster I

A super typhoon with storm surge in Leyte

Hazard

A typhoon passing over a remote and unpopulated island

Medical Effects

traumatic injuries, emotional stress, epidemic diseases and indigenous disease

Damage to critical facilities

widespread disasters can destroy or damage facilities that may be critical not only in maintaining a safe environment and public order, but also in responding to the disaster

Damage to critical facilities

Communication installations, hospitals, electrical generating and transmission facilities, water facilities, etc.

Distruption of Transportation

During the initial stages of a disaster, almost all surface menas of transportation within a community are dsirupted by broken bridges, roads, and streets that are rendered impassable by landslides or floods

Disruption of Transportation

Restricted mobility of vehicles rescue and other emergency operatio difficult

Economic Impact

Disasters disrupt normal business operations and other activities are curtailed. People must also leave their jobs and devote their time to disaster-related activities, such as search and rescue or caring for survivors

Global Environmental Change

There is increasing evidence of global climactic hange brought by both human activity and disasters

Social And Political Impact

As a large segment of the population in developing countries consists the poor, who are the most vulnerable whenever a disaster strikes, these countries are most affected. The poor e the most prone disasters because f the structures they live in which are reinforced and poorly built

Natural Hazards

naturally occuring physical phenomena caused either by rapid or slow onset of events

Biological, Geological, Hydrometeorological Hazards

Three types of natural hazards

Biological Hazard

process or phenomenon of organic origin or conveyed by biologicals vectors/agents, including exposure to the pathogenic microorganisms, toxin and bioactive substances

ebola virus, flu virus, rabies

example of biological hazard

life

bios means

Geological Hazard

geological process or phenomenon

Geological Hazard

ballistic projectiles, ground shaking, landslide, lava flow, liquefaction, tsunami

Geological Hazards

often happens as a secondary hazard because it happens after a disaster has already occured

Hydrometeorological Hazard

process or phenomenon of atmospheric, hydrologicalor oceanographic nature

water

hydro means

sky

meteoro means

earth

geo means

Man-made and Technological Hazards

also called the anthropogenic hazards

Man-made and Technological Hazards

a hazard originating from technological or industrial conditions, including accidents, dangerous procedures, infrastructure failures, specific human activities

Man-made and Technological Hazards

are induced entirely by human activities and choices

Quasi-Natural Hazards

also called, socionatural hazards

Quasi-Natural Hazards

They are associated with a combination of natural and anthropogenic factor, including environmental degradation and climate change.

Quasi-Natural Hazards

Examples of these are smog, desertification removal of support at the toe of a landslide prone slope triggering slope failure

Magnitude

Is the energy released by an earthquake at the focus; it is calculated from earthquakes recording using a seismograph

Intensity

It is the strength of an earthquake perceived by people in a certain locality generally higher ear the epicenter

Speed of Onset

How predictable a hazard is and how much time is allowed by it, is critical in determining how damaging it wil be. The more predictable an event is, the lesser the chance of incurring casualties and damages

Duration

The chance of experiencing severe damage will depend on how long the hazard affects the area.

Frequency

How often an event occurs. Sometimes frequency is expressed in terms of return period. A flood occuring every 100 years as a return period of 100 years and is then referred to as 100-year flood

Exposure

refers to the elements at risk that can be affected by hazards or are present in the hazard zones that are subject to potential losses

Environmental Dimension

refers to the geography, location and place of the population at risk; and the site, design and materials used for physical structures

Social Dimension

this includes demography; displacement and migration; level of education and literacy; health, and well-being social equity and access to basic human rights; cultural beliefs, morality

Economic Dimension

refers to the susceptibility of an economic system to the effects of a possible disaster; includes income, gross domestic product, tax revenue, investments,poverty, lack of basic services

Earthquake

the sudden release of strain energy in the Earth’s crust, resulting in waves of shaking that radiate outwards from the earthquake source

WHAT CAUSES AN EARTHQUAKE?

The tectonic plates are always slowly moving, but they get stuck at their edges due to friction. When the stress on the edge overcomes the friction, there is an earthquake that releases energy in waves that travel through the earth's crust and cause the shaking that we feel.

Faults

are fractures on the Earth’s crust where blocks of rocks move relative to one another. It can be small and localized or hundreds of kilometers long

Ground rupture

is the hazard associated with active faults. It refers to the displacement of the Earth's surface along active faults resulting in visible fracturing or cracking of the ground.

Normal Faults

are fractures in which the hanging wall has moved downward relative to the footwall.

Normal Faults

occur where two blocks of rock are pulled apart by tension.

Reverse faults

are fractures where the hanging wall has moved upward relative to the footwall.

Reverse faults

occur where two blocks of rock are forced together by compression.

Strike-Strip Faults

are fractures where the ground moves horizontally past each other.

Left-lateral strike-strip faults

are where the ground on the other side of the fault moves horizontally to the left

Right-Lateral Strike-Strip Faults

are where the ground on the other side of the fault moves horizontally to the right.

Ground Shaking

is a term used to describe the vibration of the ground during an earthquake.

Ground Shaking

is caused by body waves and surface waves.

Magnitude

The energy released by an earthquake is measured by ______

Intensity

the severity of an earthquake’s effect on people, structures, and the natural environment is measured by ________

Landslide

is the downslope movement of soil, rock, and debris due to ground shaking generated by an earthquake

• burying households and infrastructures

• block roads

• temporary damming of nearby rivers

Landslides pose threats to human life by:

Liquefaction

occurs when sediments behave like a liquid during strong ground shaking.

For liquefaction to occur

, such sediments must also be recently deposited, loosely packed, water-saturated, and sandy in composition.

Liquefaction

can cause sediment and water vents (more commonly known as sand boils) to form

Liquefaction

deform the ground and cause subsidence, swelling, undulations, and fissures.

Tsunami

is a series of waves caused by various geologic phenomena including undersea earthquakes, submarine landslides, meteor impacts, and volcanic eruptions.

LOCAL TSUNAMI

are generated by tsunamigenic events within the Philippine Region, typically within a hundred kilometers.

movement of offshore active faults and subduction zones

Typical sources of local tsunamis

FAR-FIELD/ DISTANT TSUNAMI

are those that were generated from sources in other regions surrounding the Pacific Ocean or the Celebes Sea

FAR-FIELD/ DISTANT TSUNAMI

can travel from 1 to 24 hours before reaching the coast of the Philippines.

Volcanic hazards

are observable facts that are arising due to volcanic activity such as eruption.

Volcanic eruption

is one of the dangerous event that may happen because it results to different hazards such as: Ballistic projectiles, Ash fall, Pyroclastic flows, Lava flows, Volcanic gases, Debris Avalanche or Volcanic landslide and even Tsunami.

Ballistic projectile

are rock fragments that are ejected from volcano’s mouth that are comparable to cannonballs. These reach its projectile up to 5 kilometers or 3 miles.

Ash fall or Tephra

fall are minute volcanic particles such as pulverized rock, minerals and silicon which has fine to coarse grain

Ash fall or Tephra

. This is formed during explosive volcanic eruption when dissolve gages in magma escape violently into the atmosphere.

Pyroclastic Flows

contain a highly-density mix of hot lava blocks, pumice, ash and volcanic gases

Pyroclastic Flows

They move at very high speed down volcanic slopes, typical following valleys. It consists of two parts: a lower (basal) flow of coarse fragments that moves along the ground, and a turbulent cloud of ash that rises above the basal flow

Lava flows

are streams of molten rocks that are poured or oozed from an erupting vent

Lahars

rapidly flowing thick mixture of volcanic sediments and water, occur immediately after an eruption or become long term problem if there is voluminous pyroclastic materials erupted

Lava flows

rarely threaten human life because it moves slowly. It is mostly characterized as quite effusion of lava

Volcanic gases

As magma rises towards the surface and pressure decreases, ______ are released from the liquid portion of the magma (melt) and continue to travel upward and are eventually released into the atmosphere

Debris Avalanche or Volcanic landslide

massive collapse of a volcano, usually triggered by an earthquake or volcanic eruption

Tsunami

sea waves or wave trains that are generated by sudden displacement of water