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Types of Natural Disasters

1. Earthquakes2. Tsunamis3. Volcanic Eruptions4. Cyclones5. Floods

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EARTHQUAKEAn earthquake (also known as a quake, tremor or temblor) is the perceptible shaking of the surface of the Earth. They result from the sudden release of energy in the Earth's crust that creates seismic waves. The seismicity, seismism or seismic activity of an area refers to the frequency, type and size of earthquakes experienced over a period of time.Earthquakes are measured using observations from seismometers. The moment magnitude is the most common scale on which earthquakes larger than approximately 5 are reported for the entire globe. The more numerous earthquakes smaller than magnitude 5 reported by national seismological observatories are measured mostly on the local magnitude scale, also referred to as the Richter magnitude scale. 

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Causes:-Earthquakes are the vibrations caused by rocks breaking under stress.

The underground surface along which the rock breaks and moves is called a fault plane.

Most earthquakes are causally related to compressional or tensional stresses built up at the margins of the huge moving lithospheric plates that make up the earth's surface.

The immediate cause of most shallow earthquakes is the sudden release of stress along a fault, or fracture in the earth's crust, resulting in movement of the opposing blocks of rock past one another.

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Effects:-Shaking and ground rupture are

the main effects created by earthquakes.

Earthquakes, along with severe storms, volcanic activity, coastal wave attack, and wildfires, can produce slope instability leading to landslides, a major geological hazard. 

Earthquakes can cause fires by damaging electrical power or gas lines.

Soil liquefaction occurs when, because of the shaking, water-saturated granular material (such as sand) temporarily loses its strength and transforms from a solid to a liquid. Soil liquefaction may cause rigid structures, like buildings and bridges, to tilt or sink into the liquefied deposits.

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MANAGEMENT:-Hence, in case of an earthquake, the safest place to be would be in an open ground – away from all kinds of buildings and tall structures.If you can not rush out of your building, you can duck under some sturdy desk etc. which might provide protection against heavy objects falling on your body.If even that is not possible, sit against a wall, with your back pushing the wall firmly, and, lean forward – to take your head in between both your knees, and, put your hands at the back of your head – to provide protection to your head and spine.Or, you could stand directly below one of the door-frame in your house. This one appears a bit strange to many people. In fact, there are jokes that after an earthquake – you don’t see all those door-frames standing. So, what's the reasoning behind advising people to stand below door-frames? In most styles of construction, doorframes are made very strong, or, would have a “RCC beam” running right above these frames. Either way, this “strong” structure would take the impact of objects falling from above, and, would break the impact of the heavy objects falling on the person. If you use this posture, remember to save your arms and fingers from swaying doors etc. If not careful, they could cause damage by chopping off fingers etc. due to the banging of the doors against the frame.

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TsunamiTsunamis are long-wavelength, long-period sea waves produced by the sudden or abrupt movement of large volumes of water. In the open ocean the distance between wave crests can surpass 100 kilometres (62 mi), and the wave periods can vary from five minutes to one hour.

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MANAGEMENT:-

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Step 1:- Learn about the potential for danger in advance.  It is important to consider whether or not you live somewhere that could potentially face a tsunami. It is likely that you are at some risk if: Your home, school, or workplace is in a coastal region, near the sea.The elevation of your home, school or workplace is at sea level or fairly low and on flat or only slightly undulating land. If you don't know the elevation level of your home, school or workplace, find out. Some local authorities use elevation as a warning indicator.There are warning signs indicating that your area is prone to tsunamis.Your local authorities have issued information about the potential for tsunamis.Natural sea barriers such as levees of dunes have been removed for development.

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Step 2:- Be aware if tsunamis have struck your coastal region in the past. 

Do some library research or ask at the local government office. FEMA has a website enabling online flood risk searches. Most tsunamis happen in what's called the "ring of fire," an area in the Pacific ocean known for its geologic activity. Chile, the western United States, Japan, and the Philippines are especially vulnerable.

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Step 3:- Prepare essential materials in an easy-to-obtain location. 

If a tsunami (or other natural disaster) hits, chances are you'll need a few survival items, and you'll need them fast. It can be helpful to have both a safety and survival pack already assembled: Make a safety pack. Food, water, and a first aid kit are among the basics required. Keep the safety pack somewhere obvious, well-known to everyone in the building and easy to grab in an emergency. It can also help to leave a raincoat or other coat for each person near the safety pack.Make a personal survival pack for each person in the family, and a family survival pack with common items for everyone. Include a supply of necessary medications for each member of the family. Don't forget survival items for your pets.

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Step 4:- Develop an evacuation plan. An evacuation plan must be prepared in advance to be of use. In developing

one, consider your family, your workplace, your school, and your wider community. If necessary, begin to develop a community-wide evacuation plan if nothing is being done in your community. Take the initiative to start developing the plan, and involve local authorities and other residents. Lack of evacuation plans and local warning systems put you, your family and your entire community at increased risk for injury or death during and after a tsunami.  These are the things that should be part of a successful evacuation plan: Discuss with family, and colleagues the various options for evacuation. Know, for example, where you might reunite with your loved ones should a tsunami hit.Conduct practice drills to ensure that all members of the community are clear about what they need to do and where they need to go during a safety evacuation.Include a plan that can ensure a head count of every single member of the community; ensure that assistance for disabled or ill persons can be provided.Ensure that warning and evacuation signals are understood by the community in advance — distribute pamphlets or give lectures to ensure that everybody is aware. Read Understand Tsunami Notification Terms.Remember to provide multiple safety routes owing to the possibility of an earthquake destroying roads and other infrastructure, preventing exit using some routes.Consider what types of sheltered areas might exist in the evacuation zones; do such shelters need to be built in advance?

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Step 5:- Abandon belongings. If a tsunami hits, save lives, not possessions. Trying to retrieve things and

belongings may hamper your escape by causing you to lose valuable time. Grab your safety pack, something to keep you warm, your family and leave immediately. Tsunami survivors act quickly, and usually don't bother with trying to save possessions.

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Step 6:- Move inland, and to high ground.  The first thing you should try to do, if possible, is to move away from the coast, lagoons or other bodies of water, towards higher ground and even into hills or mountains. Move until you are either 2 miles (3,200 m) inland or 100 feet (30 m) above sea level. Expect roads to be totally wiped out by a tsunami. If you're planning on using roads to get where you need to go, think again. In a full-blown tsunami, many roads will be wiped out, either by the seismic activity of the earthquake or by the tsunami itself. Have a good sense of the general direction you want to be heading in, and consider keeping a compass in your survival pack.

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Step 7:- React quickly if you are caught up in the water. If you did not manage to evacuate but find yourself caught up in the tsunami

for one reason or another, there are things that you can do to try and survive: Grab onto something that floats. Use a floating object as a raft to keep yourself above the water. Items that float such as tree trunks, doors, fishing equipment etc. may be in the water with you.

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Volcanic Eruption

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MANAGEMENT:-

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Cyclone

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MANAGEMENT:-

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FloodA flood is an overflow of any amount of water that reaches land. Floods occur usually when the volume of water within a body of water, such as a river or lake, exceeds the total capacity of the formation, and as a result some of the water flows or sits outside of the normal perimeter of the body. However, floods may be secondary effects of earthquakes, if dams are damaged. Earthquakes may cause landslips to dam rivers, which collapse and cause floods.

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Causes:-very heavy rainfall (say: due to

cyclones, typhoons etc.) in a short span of time. It should be noted that the amount of rainfall itself is not a sufficient cause, the duration within which the rainfall is receive is equally important contributor.

breach in levy, dams etc.very high tidal waves (sometimes

in the aftermath of a seismic activity, e.g. earthquakes) etc.

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Effects:-During floods (especially flash

floods), roads, bridges, farms, houses and automobiles are destroyed. People become homeless. Additionally, the government deploys firemen, police and other emergency apparatuses to help the affected. 

The environment also suffers when floods happen. Chemicals and other hazardous substances end up in the water and eventually contaminate the water bodies that floods end up in.

Additionally, flooding causes kills animals, and others insects are introduced to affected areas, distorting the natural balance of the ecosystem.

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MANAGEMENT:-Sea walls and tide gates have been built in some places to prevent tidal waves from pushing the waters up ashore. In some areas too, sand bags are made and placed in strategic areas to retain floodwaters.

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In some places, retaining walls levees, lakes, dams, reservoirs or retention ponds have been constructed to hold extra water during times of flooding.In some places, retaining walls levees, lakes, dams, reservoirs or retention ponds have been constructed to hold extra water during times of flooding.Trees, shrubs and grass help protect the land from erosion by moving water. People in low-lying areas must be encouraged to use a lot of vegetation to help break the power of moving flood water and also help reduce erosion.These are small reservoirs built and connected to waterways. They provide a temporary storage for floodwaters. This means in an event of flooding, water is drained into the basin first, giving people more time to evacuate. It can also reduce the magnitude of downstream flooding.