Natural Hazards

A natural hazard is a natural event that has the potential to cause harm. A natural disaster is the actual negative impact of a natural event on humans.

Hurricanes

A Hurricane is a large and powerful storm that causes destruction. Hurricanes are formed over ocean surface temperature that has to be 25°C. The hot air then goes up to meet the cool atmosphere. With the assistance of cool air and Coriolis force, this creates a hurricane.

Different stages of a hurricane:

• Tropical wave - a low pressure persisting winds that blow from east to west

• Tropical disturbance - an organized series of thunder storms that last more than 24 hours and is accompanied by heavy rains and gusty winds.

• Tropical depression -  the storm gains a definite counter-clockwise with sustained wind speeds less than 39 mph.

• Tropical storm - the storm becomes more organized with sustained wind speeds of 39 to 93 mph; at this pint it receives a name.

• Hurricane - the final, mature stage that sustains 94 mph and higher and a well defined, calm eye forms in the center.

A hurricane warning is when the NHC issues a statement about a hurricane that is expected near a coastal area. A hurricane watch is when the NHC issues a statement about possible hurricane conditions within 48 hours.

The saffir-simpson scale:

• Category 1 - 74-94 mph

• Category 2 - 95-110 mph

• Category 3 - 111- 129 mph

• Category 4 - 130-158 mph

• Category 5 - over 157

Advantages of a Hurricane

• Evens the topsoil layer

• Property and living values go up due to repairs

• Brings people together during the aftermath

• Lowers the temperature for a certain time

• Helps build coastal islands, making islands wider

Disadvantages of a Hurricane

• Destruction of infrastructure 

• Causes floods which wash away homes and people

• Strong winds destroy trees and scoop up people and uses them as missiles causing chaos

• Loss of life will lessen the labor force

• Lack of livestock and crops leading to sourcing food from other foods

Natural hazards caused by Hurricanes

• Lighting

• Flooding

• Land slides

• Heavy rains

• Tornadoes

• Strong Currents

Effects of a hurricane

Enviromental

Short - term

• built landscape destroyed

• natural hazards occurs

Long - term

• important land marks may become lost

Economical

Short - term

• businesses destroyed

• looting

Long - term

• cost of rebuilding is high

• income becomes lost

Social

Short - term

• death & injury

• transportation and communication is lost

Long - term

• diseases

• displaced families

A storm surge is the rise in sea water that is generated by storms like hurricanes.

Measures to take BEFORE, DURING and AFTER a hurricane.

BEFORE

• stock up on non perishables

• have a first-aid kit

• have a battery powered radio

• have flashlights

• have extra batteries in air tight containers

DURING

• use flashlights

• listen to radio

• remain inside

AFTER

• be careful of fallen wires

• check up on family members

Earthquakes

• Core (inner) - the hottest part of the Earth and it is in the center

• Core (outer) - the surrounding layer of the inner core. It is liquid and extremely hot

• Mantle - the widest part of the Earth. It is made up of a semi-molten rock called magma.

• Crust - the thinnest part of the Earth. It is made up of solid rock on which we live.

An earthquake (or quakes/tremors) is shaking of the surface of the Earth caused by sudden movement in the Earth's crust. They can be extremely violent. Earthquakes are formed by the sudden release of stored energy in the earth's crust caused by movements of tectonic plates like.

Positive effects

• Formation of new land forms

• Exposure of valuable minerals

• Natural churning of soil

Negative Effects

• Destruction of Infrastructure

• Significant loss of life

• Tsunamis may come before or after

IMAPACTS OF EARTHQUAKES

Social

Short Term

• Death or injury

• Transport and Communication Destroyed

Long Term

• Diseases

• Displaced families

Economical

Short Term

• Business are destroyed

• Looting

Long Term

• Cost of rebuilding is high

• Income could be lost

Enviromental

Short Term

• Built landscape is destroyed

• Natural disasters may occur (fires, tsunamis, landslides, flooding)

• Important human and natural landmarks may be lost

Volcanic Eruptions

A volcanic eruption occurs when magma is released from a volcano. Four materials which may be ejected may be:

• Ash

• Lava

• Steam

• Volcanic Ash

A volcano is a rupture in the Earth's crust where molten lava, hot ash and gases from below the earth's crust escape into the air. Volcanos are formed when magma reaches the Earth's surface, causing eruptions of lava and ash. They occur at destructive and constructive plate boundaries.

Positive effects

• Dramatic scenery attracts tourism

• Creates fertile soil which is good for agriculture

• Heat is good for Geothermal energy

Negative effects

• Loss of life

• Creates mudflows vcalled lahars

• Destruction of settlements

• Landscapes are destroyed

Natural hazards from a volcanic eruption

• Volcanic ash

• Land slides

• Lahars (Volcanic Mudflow)

• Tsunami

EFFECTS OF A VOLCANIC ERUPTION

Social

Short Term

• Deaths

•  injuries

• evacuations

• trauma

Long term

• Communities relocated

• health issues

• heritage loss

Enviromental

Short Term

• Ash blocks sun

• lava burns land

•  air/water polluted

Long term

• Fertile soil

•  new landforms

• climate changes

Economical

Short Term

• Homes, roads, farms destroyed

•  costly aid

Long term

• Tourism grows

• farming improves

• rebuilding costs

MEASURES TO TAKE BEFORE A VOLCANIC ERRUPTION

• Monitor volcanoes with sensors and satellites

• Plan safe zones and evacuation routes

• Train communities with drills and education

• Stockpile emergency supplies (food, water, masks)

• Build barriers to redirect lava

• Share data and aid internationally