Acknowledgement- WikipediaCertificate- Under the guidance of Rajendra sir

SST PROJECT

DISASTERS

BY-NAME- ANOUSHKA BASUCLASS- 9-B

Types of disasters.

Disaster management.

Earthquakes.

Avalanches.

Index

What is a disaster?

Disaster refers to a sudden event, such as an accident or a natural catastrophe, that causes great damage or loss of life.

Types of Disasters

Disasters can be broadly classified into two types-

Natural disasters

Man- made disasters

A natural disaster is a major adverse event resulting from natural processes of the Earth. This may cause loss of life and could also cause economic damage.

Some examples of natural disasters are-FloodsEarthquakesVolcanic eruptionsAvalanchesTsunamisHurricanes

Natural disasters

Disasters caused by human activities that has an adverse effect are called man made disasters.

Some examples of man-made disasters areNuclear explosionGlobal warmingOil spillsStampedesFires

Man – made disasters

Disaster management

Disaster management (or emergency management) is the creation of plans to decrease the impact of disasters and cope with disasters.

What is disaster management?

Phases of disaster management

Disaster Preparedness-activities prior to a disaster.

Disaster Response –activities after a disaster.

Disaster recovery-activities taken place for recovery from the disaster

Disaster Mitigation –activities that reduce the effect of disasters.

Preparedness

Response

Recovery

Mitigation

Earthquakes

An Earthquake is the shaking of the surface of the Earth. It is the result of a sudden release of energy in the earth’s crust that creates seismic waves.

The seismic activity of an area refers to the frequency , type and size of earthquakes experienced over a period of time.

The severity of the shaking can range from barely felt to violent enough to toss people around. Earthquakes have destroyed whole cities.

What is an Earthquake?

What causes an Earthquake?Tectonic plates are always in motion. When two blocks of rock

or two plates rub against each other, they get stuck to each other due to friction(because of the irregularities , such as rocks found on their surfaces).

The rocks or the plates push against each other but do not move. After a while, there is a crack in the plates or the rocks break because of all the pressure that's built up.

This leads to the production of energy in the state of vibrations.

Which are felt as huge tremors called Earthquake.

THE RICHTER SCALEThe intensity and strength of an earthquake is

measured on , the scale invented by Charles Richter in 1935. Which categories earthquake on the basis of energy released.

Each point increasing on the scale indicates ten times the

amount of shaking and 33 times the amount of energy released .

Measurement of an Earthquake

Sir Charles Richter

4- Minor Earthquake

5 - Moderate Earthquake

6 - Strong Earthquake

7 - Major Earthquake

8 - Great Earthquake

Measurement on the Richter scale

SEISOMOGRAPH

A seismograph is an instrument used for recording the intensity and duration of an earthquake.

Focus (Hypocenter) :Focus is the point on the

fault where rupture occurs and the location from which seismic waves are released.

Epicenter :Epicenter is the point on

the earth’s surface that is directly above the focus ,the point where an earthquake or underground explosion originates.

IMPORTANT TERMS

DROP, COVER AND HOLD ON!

Stay outdoors, if indoors run outside and find an open area.

Stay away from windows.

If you’re in bed, hold on and stay there, protecting your head with a pillow.

If you’re outdoors, find a clear spot away from buildings, trees and power lines. Then, drop to the ground.

If you’re in a car, slow down and drive to a safe place. Stay in the car until the shaking stops.

What to do during an Earthquake?

Avalanches

An avalanche is a rapid flow of snow down a sloping surface or a mountainside. It could also be compared to a landslide with snow instead of earth. Avalanches are also called snowslide or snowslip.

What is an avalanche?

Loose Snow AvalancheThese avalanches are commonly seen just after a

snow fall. Since the snow does not have time to settle down fully or has been made loose by sunlight, the snow-pack is not very solid,which enables it to slide down.

These avalanches speed up to 300km/h.These avalanches force upto 50 tones/m sq

Types of Avalanches

Slab avalanchesLoose Snow Avalanches in turn could cause a

Slab Avalanche, which are characterized by the fall of a large blocks of ice down the slopes.

Thin slabs cause fairly small amounts of damage, while the thick ones are responsible for many fatalities and injuries.

Speeds upto 10-150 km/h

Powder Snow AvalanchePowder Snow Avalanches are a mix of the other

forms, Loose Snow and Slab. The bottom half of this avalanche consists of a

slab or a dense concentration of snow, ice and air. Above this is a cloud of powdered snow, which can snowball into a larger avalanche as it progresses down the slope.

Speeds upto 500 km/h

Snowstorm and Wind Direction: Heavy snowstorms are more likely to cause Avalanches. Wind normally blows from one side of the slope of mountain to another side. While blowing it moves the snow which causes an avalanche.

Heavy snowfall: Heavy snowfall deposits snow in unstable areas and puts pressure on the snow-pack. Precipitation during the summer months is the leading cause of avalanches.

Causes of Avanlanche

Vibration or Movement: The use of All Terrain Vehicles and Snowmobiles creates vibrations within the snow that it cannot withstand. Coupled with the gravitational pull, it is one of the quickest ways to cause an avalanche. The other is construction work done with explosives, which tend to weaken the entire surrounding area.Earthquakes could also lead to an avalanche.

Recognize where one is most likely to occur.  If you understand that there is a high

possibility of an avalanche, you are less likely to fall victim to the surprise occurrence of one.  

By understanding how the path of an avalanche appears.  

How to avoid getting caught in a avalanche?