HAZARDS & GEOLOGICAL HAZARDS

hazard

is a source or a situation with the

potential for harm in terms of human injury

or ill-health, damage to property, damage to

the environment, or a combination of these.

unwanted event

is a situation or

condition where there is a loss of control of

the hazard that leads to harm.

Hazards

- can include latent conditions that

may represent future threats and may have

different origins.

- is

characterized by its location, intensity and

probability of occurrence.

Hazards

know no politics, race or creet it could strike anytimw

points on triangular or diamond-

shaped signs

are similarly used to

indicate warning and danger, and reflect

instability and conflict.

bright yellow or red

for visibility

and to highlight the blatant nature of the

shape.

• Natural Hazards

• Human-induced Hazards

Hazards can be classified into:

emergency management cycle

- can greatly help in making the community

more disaster-resilien

Emergency management

aims to reduce or

avoid the potential losses from hazards,

assure prompt and appropriate assistance to

damaged materials, and achieve rapid and

effective recovery.

Mitigation

- Activities designed to alleviate the

effects of a major disaster/emergency or

long-term activity minimizing the

potentially adverse effects of future

disaster in affected areas.

Preparedness

- Activities, programs, and systems that

exist prior to an emergency and that are

used to support and enhance response

to an emergency or disaster. This phase

implies that risks, hazards and

vulnerabilities have been assessed.

Response

- Activities and programs designed to

address the immediate and short-term

effects of the onset of an emergency or

disaster such as artifacts salvage and

relocation within 48 - 72 hours.

Recovery

- Long-term activities and programs

beyond the initial crisis period of an

emergency or disaster designed to return

all systems to normal status or to

reconstitute these systems to a new, less

vulnerable condition.

Recovery

Upon completion

of the post-emergency critique, it is

possible to update plans and implement

corrective actions.

Humanitarian action/agencies

- During a disaster, ____________ are

often called upon to deal with immediate

response and recovery.

Leadership

is important for a disaster risk

reduction management plan to be effective

Leaders

must be guided in science in order to make the right decisions in preventing natural hazards from becoming disasters

humanitarian agencies

must have experienced leaders, trained personnel, adequate transport and logistic support, appropriate communications, and guidelines for working in emergencies.

Geological hazard

- It is an extreme natural event in the crust of

the Earth that pose a threat to life and

property

Geological hazard

for example, earthquakes, volcanic

eruptions, tsunamis (tidal waves) and

landslides.

Earthquake hazards

- are generally classified

as primary and secondary hazards.

Primary earthquake hazards

They are the direct results of the movements of the

ground.

• Ground shaking

• Landslides and rockfalls

• Surface rupture

• Liquefaction

primary earthquake hazards:

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.

ground shaking

the severity

of _______ increases as magnitude

increases and decreases as distance from the

causative fault increases.

Mercalli Scale

is based on observable

earthquake damage.

Mercalli

is based on

observable data which can be subjective

Richter Scale

- measures the energy released by an

earthquake using a seismograph.

Seismogram

- is a record of the seismic waves from an

earthquake.

seismograph or seismometer

is the measuring instrument that creates

the seismogram.

Landslides and Rockfalls

are often caused by erosion of

earth around larger rocks that then become

loose and fall. earthquakes can also lead to this

Surface rupture

- is the visible offset of the ground surface

when an earthquake rupture along a fault

affects the Earth's surface.

Liquefaction

- is a phenomenon in which the strength and

stiffness of a soil is reduced by earthquake

shaking or other rapid

loading.

Liquefaction and related

phenomena

have been responsible for

tremendous amounts of damage in historical

earthquakes around the world.

Secondary earthquake hazards

They are the results of the primary hazards

which can be proven to be more catastrophic

Secondary earthquake hazards

• TSUNAMI

• SEICHE

• FLOODING

• FIRES

Tsunami

- is a series of waves in a water body caused

by the displacement of a large volume of

water, generally in an ocean or a large lake.

tsunami

Earthquakes, volcanic eruptions, and other

underwater explosions above or below

water all have the potential to generate a

______

over 15,000 people

- The tsunami swept the Japanese mainland

and killed _______, mainly

through drowning, though blunt trauma also

caused many deaths.

Seiche

- is a standing wave in an enclosed or partially

enclosed body of water.

Seiches and seiche-

related phenomena

have been observed on

lakes, reservoirs, swimming pools, bays,

harbors and seas.

FLOODING

Earthquakes can indirectly cause

__________ in several ways: triggering

tsunamis, destabilizing dams, breaking

and/or lowering protective levees.

Fires

- often associated with broken electrical and

gas lines, is one of the common side effects

of earthquakes.

volcano

is a rupture in the crust of a

planetary-mass object, such as Earth, that

allows hot lava, volcanic ash, and gases to

escape from a magma chamber below the

surface

• active

• dormant

• extinct.

Volcanoes are classified as:

Active volcanoes

- have a recent history of eruptions and

they are likely to erupt again.

50 to 70

Out of the

estimated 1500 known active volcanoes

in the world today, _______ erupt

annually.

Dormant volcanoes

- have not erupted for a very long time but

may erupt at a future time.

Dormant volcanoes

They are

considered as an active threat even if

they are not exhibited any activity for a

long time.

• CINDER CONES

• SHIELD VOLCANO

• COMPOSITE VOLCANOES

By composition and structure:

• explosive(central)

• quiet (fissure)

Types of Eruption

Lahar

- is a violent type of mudflow or debris

flow composed of a slurry of pyroclastic

material, rocky debris and water.

Lava flow

- is an outpouring of lava created during

an effusive eruption.

tephra

Explosive eruptions

produce a mixture of volcanic ash and

other fragments called ________, rather

than lava flows.

Ash fall

is a flowing mixture of volcanic ash

and large angular blocks commonly

formed as a result of a gravitational

collapse of a lava dome or lava flow.

Block and ash flows

are a type of

pyroclastic flow and as such they form

during volcanic eruptions.

Pyroclastic flow

- is a dense, fast-moving flow of solidified

lava pieces, volcanic ash, and hot gases.

It occurs as part of certain volcanic

pyroclastic flow

is extremely

hot, burning anything in its path. It may

move at speeds as high as 200 m/s.

Ballistic projectiles

- are rocks that an erupting volcano may

hurl into the air.

Volcanic gases

- are gases given off by active (or, at times,

by dormant) volcanoes.