2. What is Disaster?
• Any occurrence that causes damage ecological disruption ,loss of
human life deterioration of health and health services on a scale,
sufficient to warrant an extraordinary response from out side the
affected community or area.
• (WHO) A disaster can be defined as an occurrence either nature
or man made that causes human suffering and creates human
needs that victim cannot alleviate without assistance.
4. What Is Disaster Management
1.Preparedness = Activities prior to a disaster.
Example= Preparedness plans; emergency
exercises/trainings; warning system.
2. Response = Activities during a disaster.
Example= public warning system;
emergency operation: search and recuse.
3.Recovery=Activities following a disaster .
Example= Temporary housing; claims
Processing and grants; long term medical care
4.Mitigation= Activities that reduces the affect of
Example= Building codes and zoning; vulnerability
Analyses; public and education.
20. What is an Earthquake?
An earthquake is the shaking of the surface of Earth due to the sudden release of energy in
the Earth’s crust, as a result, seismic waves (also known as S waves)are created. The seismic
activities in an area determine the type and intensity of the earthquake.
What Causes an Earthquake?
Earthquakes are caused due to sudden tectonic movements in the earth’s crust. When the
tectonic plates slide over one another, there is a cause of orogeny which results in
earthquakes and volcanoes. These disturbances cause vibrations that spread in all directions.
As there is a relative motion of these plates, there is stress built up, which breaks by releasing
the stored energy known as shock waves.
21. What to do During an Earthquake?
Before the disaster:
•Connections of gas lines and appliances must be made flexible.
•An earthquake readiness plan must be kept ready, including locating a shelter house, canned
food and up to date first aid kit, gallons of water, dust masks, goggles, firefighting equipment, a
torch, and a working battery-operated radio.
•Architects and structural engineers must be consulted before laying the foundation of buildings in
earthquake-prone areas, also the building must be manufactured as per the rules and regulations
laid by the disaster management committee.
•Awareness must be spread among friends and family members about the above-mentioned
22. Do’s and Don'ts:
•One must stay indoors until the shaking stops and it’s officially announced that it is safe to
•One must stay away from bookcases, furniture, and heavy appliances that may fall.
•The shelter must be under a table or bed, and hold on to a post or any other fixture.
•If one is outdoors, the shelter must be taken in a clear stop away from buildings, trees, and
23. After the disaster:
The following are the measures that must be undertaken after the calamity is over.
•First aid kits must be used to tend to persons with minor injuries such as bleeding and bruises. Whereas seriously
injured individuals must not be moved until they are out of danger and proper medical help has arrived.
•If the person is not breathing, rescue breathing must be administered. If the person has no pulse, CPR must be given.
•Tumbling shelves and falling items must be taken care of and damaged walls made of bricks must be avoided.
•Main gas valves must be checked for leaks. The main power switch must be turned off if there is a possibility of
damage. Broken appliances must be unplugged until the damage is repaired.
24. What are the Effects of an Earthquake?
Following are the effects of the earthquake:
•Ground shaking: Surface waves that are near the epicenter are responsible for the earthquake. The intensity of
ground shaking depends on the duration, local geology, and distance.
•Damage to a man-made structure.
•An outbreak of fire and spilling of hazardous chemicals.
27. What is a Tsunami?
1. The series of extremely long waves, Tsunami are very long wavelengths of water caused by a large and
sudden displacement of the ocean due to earthquakes, volcanic eruptions etc.
2. These are also called seismic sea waves and are one of the most powerful and destructive natural
3. When they reach the coast, they can cause dangerous coastal flooding and powerful currents that can
last for several hours or days.
4. Most tsunamis are caused by large earthquakes. Though, not all earthquakes cause tsunamis.
28. Characteristics of Tsunami
•Tsunamis are among Earth’s most infrequent hazards and most of them are small and nondestructive.
•Over deep water, the tsunami has very long wavelengths (often hundreds of kilometers long) when a tsunami
enters shallow water, its wavelength gets reduced and the period remains unchanged, which increases the
•Tsunamis have a small amplitude (wave height) offshore. This can range from a few centimetres to over 30 m
in height. However, most tsunamis have less than 3 m wave height.
•It radiates in all directions from the point of origin and covers the entire ocean.
•It generally consists of a series of waves, with periods ranging from minutes to hours.
29. Causes of Tsunami
How are Tsunami generated?
A Tsunami can be generated only through the vertical movement of the seafloor. Most Tsunamis are generated
by earthquakes. Volcanic eruption, underwater explosion, landslides and meteorite impacts are some other
causes of Tsunami.
The details of causes of Tsunami is explained below-
Earthquake – Tsunami is generated by the earthquake because of the disturbance of the seafloor and is formed
generally with vertical displacement. Most Tsunami is generated by earthquakes that occur along the subduction
boundaries of plates along the ocean trenches. The size of the Tsunami is related to the size of the earthquake.
Underwater explosion – A Nuclear Testing by the US generated Tsunami in 1940 and 1950s in Marshall island.
Volcanic eruption – Volcanoes that occur along the Coastal waters can cause several effects that can cause a
30. Tsunami Risk, Hazard & Mitigation Measures
The main damage from the Tsunami comes from the destructive nature of waves. The second effect of the Tsunami
includes debris acting as projectiles and the tertiary effect includes the loss of crops and water which leads to famine
2.The building of walls was done by Japan.
3.Planting trees as done in Tamil Nadu by a village
4.Proper relief and rehabilitation preparedness
5.Awareness among the masses
33. What is a hurricane?
Hurricanes are enormous storms which come with rotating wind speed of 74 miles per hour.
The rotating wind swirls across the warm water of the tropics and comes with terrifying force.
This force blast ashore which causes destruction and even death. Hurricanes are known to be
one of nature’s most destructive storms as they bring heavy rains, deadly waves and fierce
winds. Hurricanes leave its mark by hitting the land, rip up trees, cause floods and destroy
homes. Thousands of people get killed with this terrifying storm and cause a million dollars of
damage. People get homeless, everything gets swept away by these floods. Another violent
wind storm is known as Tornadoes. Tornadoes winds are more violent and stronger than
hurricane winds. Hurricanes last longer and cover up to 500000 square miles of land.
35. How do Hurricanes form?
Hurricanes are known to be the most violent storms on earth. Usually, they are formed near
the equator over the warm ocean water. Waves are produced when oceans are at their
warmest temperature, and the air above water becomes heavy with a lot of moisture.
Hurricanes typically form between 5 and 15 degrees latitude north and south of the equator.
The period during each year when hurricanes are most likely to occur in a given place is
called hurricane season. Hurricane season lasts from June to October over the Western
Pacific and in the Atlantic, it runs from June to November.
36. Stages of Hurricane:
Hurricanes go through a process of development that involves
different stages to become what they are. These stages have different
lengths depending on the environmental conditions of the place where
they are located at a particular time. If the conditions are favourable,
then a hurricane can be formed quickly; likewise, if the conditions are
unfavourable, the development can be slow. Given below in a table
are the different stages of development that a hurricane goes through:
37. Tropical Disturbance
An organised area of thunderstorms that usually forms in the tropics.
Typically, they maintain their identity for 24 hours and are accompanied
by heavy rains and gusty winds.
Tropical Wave A low-pressure trough generally moving westward with the trade winds.
A generic term for any organized low pressure that develops over
tropical and sometimes subtropical waters. Tropical depressions, tropical
storms, and hurricanes are all example of tropical cyclones.
An organized area of low pressure in which sustained winds are 38 mph
Hurricane A tropical cyclone with sustained winds of at least 74 mph.
A tropical cyclone with maximum sustained wind speed that ranges from
39 to 73 mph.
38. Some Interesting Facts About Hurricanes:
There are some facts that are related to the hurricanes:
•Hurricanes are violent storms and can travel up to 300 miles across.
•A hurricane can last for more than 14 days.
•The first hurricane every year gets a name starting with the letter A, second with B, and so on.
•There is a wall of clouds around a hurricane’s eye that is called as the eyewall. The storm’s strongest winds
exist in the eyewall.
•The deadliest hurricane in the United States hit Galveston, Texas in 1900. A storm surge 20 feet high rushed
through the whole city and more than 8000 people were killed.
42. 1. In December 1952, cold weather and windless conditions combined with all the smoke from
coal fires to cause a severe air-pollution event called the “Great Smog of London” that lasted
five days and killed a total of 12,000 people.
43. London had suffered from poor air quality since the 13th century and was
quite accustomed to heavy fogs. But on December 4, 1952, an anticyclone
settled over a windless London causing a temperature inversion with cold,
stagnant air trapped under a layer of warm air. The resultant fog mixed with
smoke from home and industries, vehicles, and other pollutants such as
sulfur dioxide to form smog. According to UK’s Met Office, 1,000 metric
tons of smoke, 140 metric tons of hydrochloric acid, 14 metric tons of
fluorine compounds, and 800 metric tons of sulfuric acid were emitted into
the atmosphere each day that month.
The smog was so thick, the visibility was down to a meter during the day
making it extremely difficult to go anywhere. Public transport, apart from the
London Underground, ceased, and ambulance services stopped. To go out
meant shuffling one’s feet to feel for obstacles, but there was no panic as
people were used to London fogs.
44. In the weeks that followed, however, the medical services found out at least
4,000 people died due to the fog. The following year it was suggested in the
House of Commons that 6,000 had died and 25,000 more claimed to fall sick
because of the fog. More deaths followed in the coming months due to
respiratory tract infections, hypoxia, and obstruction in lungs due to smog-
related infections. Recent research has put the number of fatalities as
considerably larger than the contemporary estimates of 12,000. The Great
Smog of London is considered the worst air-pollution event in the history of
the UK and led to the Clean Air Act 1956, as well as several changes in
practices and regulations.
46. 2. On December 20, 1987, the seriously overcrowded Philippine ferry MV Doña Paz sank after
colliding with an oil tanker. It was the worst peacetime, maritime disaster in history as 4,386
people died because the ship had no radio and the lifejackets were locked away.
47. MV Doña Paz was on its way to Manila from Tacloban, Leyte, when it collided with the MT
Vector, an oil tanker carrying 1,050,000 liters (1,041 metric tons) of gasoline and other
petroleum products. Vector’s cargo caught fire which spread to the Doña Paz causing
panic. According to accounts by survivors, the lifejackets, which were later believed to have
been locked away, couldn’t be found. The crew ran around in panic as well instead of giving
orders and organizing the passengers for evacuation.
Several people jumped off the ship and swam among the charred bodies with the fuel still
on fire on the surface of the water. Some used suitcases to help them float in the shark-
infested Tables Strait. Doña Paz sank in two hours and so did Vector two hours later. The
crew, medics, and officers of MS Don Claudio, a passing inter-island ship who witnessed
the explosion, tried to help the survivors but could only save 24 passengers from the Doña
Paz and two crew members of the Vector. The Philippine maritime authorities only
reportedly found out about the incident eight hours later, and it took them another eight
hours to organize a rescue
49. 3. In 1626, the Wanggongchang Gunpowder Factory in Beijing, China, exploded destroying
part of the city and killing 20,000 people.
50. The “Wanggongchang Explosion” on the morning of May 30 was
so loud, the rumble was heard as far as 150 kilometers (93 miles)
away according to contemporary accounts, and the debris flew as
far as to 30 kilometers (18.6 miles). The explosion, however, did
not cause any fire damage, but its force stripped the victims of
No one knows what caused the explosion though various
theories, including a gunpowder explosion, meteoroid crash, and
natural gas explosion were put forth. Crown Prince Xianchong,
aged one, died in the explosion and the Tianqi Emperor, the
ruling emperor at that time, believed it to be a punishment from
52. 4.In 1975, a “once-in-2000-years” flood caused the failure of the Banqiao Dam in China killing
230,000 people and collapsing nearly six million buildings. Though officially the failure was
claimed to be a natural disaster, reducing safety features during construction is believed to be
53. Despite China’s foremost hydrologist, Chen Xing’s, advice to
build 12 sluice gates, the Chinese government, which was
consulting Soviet engineers, decided to build only five sluice
gates. Safety features were similarly reduced in other dam
projects and Chen was fired for criticizing the government’s
decision. In early August 1975, Typhoon Nina hit Taiwan and
though it weakened by the time it reached China, it produced a
torrential rain of more than 400 millimeters (16 inches), the
heaviest being along Banqiao Dam with 1,631 millimeters (64.2
inches), 830 millimeters (33 inches) which fell in just six hours.