Detailed information about Natural Disasters in two categories: 1. Hydro-meterological Disasters 2. Geological Disasters

1. Natural Disaster
Hazard is an event that has potential for causing injury/ loss of life or damage to
property/environment. Disaster is an event that occurs suddenly/unexpectedly in most
cases and disrupts the normal course of life in affected area.
Environmental hazards are those extreme events caused by natural process or man's
activities which exceed the tolerable magnitude within or beyond certain time limits and
make adjustments difficult and thus result in loss of property and lives, such as
earthquakes, floods, volcanic eruptions etc.
Vulnerability refers to the susceptibility to loss of human life, physical injury, or economic
loss of livelihoods and assets when exposed to hazard events [6,7]. The extent of
vulnerability depends on the construction, predisposition, fragilities, inherent capacity, or
weakness of the exposed elements
A natural disaster is "the negative impact following an actual occurrence of natural
hazard in the event that it significantly harms a community".

2. Classification of natural hazards with examples of events

3. Core topics of hazards and disaster

9. Hydro-meteorological Based Disasters
Tropical cyclones, heavy rainfall, severe thunderstorms, floods and drought are hydro-
meteorological hazards whereas earthquakes and volcanic eruptions are grouped
under geological hazards. Landslides and avalanches are caused by a combination of
geological and hydro-meteorological factors.
7 most common hydro meteorological disasters:
Floods, storm surges, landslides, avalanches, hail, windstorms, droughts, heat waves
and forest fires are a few examples of hydro-meteorological hazards that pose a
significant risk.
Hydrometeorological hazards are caused by extreme meteorological and climate
events, such as floods, droughts, hurricanes, tornadoes, landslides, or mudslides.

10. Hydro-meteorological hazards (HMHs) have had a strong impact on human societies and
ecosystems. Their impact is projected to be exacerbated by future climate scenarios.
HMHs cataloguing is an effective tool to evaluate their associated risks and plan
appropriate remediation strategies.

12. Flood

13. Floods are the most frequent type of natural disaster and occur when an overflow of
water submerges land that is usually dry. Floods are often caused by heavy rainfall,
rapid snowmelt or a storm surge from a tropical cyclone or tsunami in coastal areas.
The adverse effects of flooding include:
1. Loss of human life.
2. Property and infrastructure damage.
3. Road closures, erosion, and landslide risks.
4. Crop destruction and livestock loss.
5. Threats to salmon and other aquatic species.
6. Health risks due to water contamination.
7. Housing displacement.
8. Economic impacts.

14. Flash Flood

15. Flash flood: A flood caused by heavy or excessive rainfall in a short period of time,
generally less than 6 hours. Flash floods are usually characterized by raging torrents
after heavy rains that rip through river beds, urban streets, or mountain canyons
sweeping everything before them.
Flash floods are defined as those flood events where the rise in water is either
during or within a few hours of the rainfall that produces the rise. Therefore, flash
floods occur within small catchments, where the response time of the drainage
basin is short.
Most famous flash flood examples:
Mississippi River flood of 1927, also called Great Flood of 1927, flooding of the
lower Mississippi River valley in April 1927, one of the worst natural disasters in the
history of the United States.

17. The associated convective cloud can extend up to a height of 15 kilometres (9.3 mi)
above the ground. During a cloudburst, more than 20 millimetres (0.79 in) of rain may
fall in a few minutes. The results of cloudbursts can be disastrous. Cloudbursts are also
responsible for flash flood creation.
cloudburst, a sudden, very heavy rainfall, usually local in nature and of brief
duration. Most so-called cloudbursts occur in connection with thunderstorms. In
these storms there are violent uprushes of air, which at times prevent the
condensing raindrops from falling to the ground
A cloudburst is an extreme amount of precipitation in a short period of time,
sometimes accompanied by hail and thunder, which is capable of creating flood
conditions. Cloudbursts can quickly dump large amounts of water, e.g. 25 mm of
precipitation corresponds to 25,000 metric tons per square kilometre

18. Drought is a prolonged dry period in the natural climate cycle that can occur anywhere
in the world. It is a slow-onset disaster characterized by the lack of precipitation,
resulting in a water shortage. Drought can have a serious impact on health, agriculture,
economies, energy and the environment.
Drought

19. Drought can also cause long-term public health problems, including: Shortages of
drinking water and poor quality drinking water. Impacts on air quality, sanitation and
hygiene, and food and nutrition. More disease, such as West Nile Virus carried by
mosquitoes breeding in stagnant water.
Drought is caused by a lack of rainfall, causing serious water shortages. It can be fatal.
Unlike other extreme weather events that are more sudden, like earthquakes or
hurricanes, droughts happen gradually.
A drought is a period of time when an area or region experiences below-normal
precipitation. The lack of adequate precipitation, either rain or snow, can
cause reduced soil moisture or groundwater, diminished stream flow, crop damage,
and a general water shortage.

20. Cyclone

21. Cyclones are caused by atmospheric disturbances around a low-pressure area distinguished
by swift and often destructive air circulation. Cyclones are usually accompanied by violent
storms and bad weather.
A tropical cyclone brings very violent winds, torrential rain, high waves and, in some
cases, very destructive storm surges and coastal flooding. The winds blow
counterclockwise in the Northern Hemisphere and clockwise in the Southern
Hemisphere.
Cyclones - Natural Disasters - Earth watching. Cyclones, Hurricanes and Typhoons are
powerful storms that have winds in excess of 119 kilometres per hour (74 MPH).
The most severe cyclone to make landfall in India in the past 12 months was »Asani«. It
reached a wind speed of up to 94 km/h on May 11, 2022 at 5:30 am local time near
Bapatla and was 19 kilometers in diameter at the time.

22. Forest Fires

23. Forest fires are wildfires that spread uncontrollably, burning plants, animals, grasslands
and brush lands that fall in their path. The wind spreads the fire rapidly, causing
significant air pollution. Generally, fires that continue for longer or are highly
inflammable are caused by climatic changes.
Major Forest Fires in 2021
1. Wildfires in Siberia affected the western region around Tyumen and Omsk in early
2021. As per the Moscow Times, nearly 40 million acres of land have burned down in
Siberia. The eastern part of the region, like the Sakha Republic in the northeast,
suffered major damage.
2. North America saw extreme temperature and heat waves in July and August. Lytton
city in Canada recorded a temperature of 49.6 degrees Celsius, causing a series of
wildfires.
3. The Mediterranean region suffered major wildfires leading to an increase in PM
levels up to 2.5. Turkey, Tunisia and Italy suffered the worst wildfires.
Effects of Forest Fire
1. Forest fires can impact the economy as many families and communities depend on
the forest for food, fodder and fuel.
2. It burns down the small shrubs and grasses, leading to landslides and soil erosion.

24. Geological Based Disasters

26. Earthquake

27. An earthquake is a violent and abrupt shaking of the ground, caused by movement between
tectonic plates along a fault line in the earth's crust. Earthquakes can result in the ground
shaking, soil liquefaction, landslides, fissures, avalanches, fires and tsunamis.
An earthquake is caused by a sudden slip on a fault. The tectonic plates are always slowly
moving, but they get stuck at their edges due to friction.
The effects from earthquakes include ground shaking, surface faulting, ground failure,
and less commonly, tsunamis.
We cannot prevent natural earthquakes from occurring but we can significantly mitigate
their effects by identifying hazards, building safer structures, and providing education on
earthquake safety. By preparing for natural earthquakes we can also reduce the risk from
human induced earthquakes.
Depths of earthquakes gives us important information about the Earth's structure and
the tectonic setting where the earthquakes are occurring. The most prominent example
of this is in subduction zones, where plates are colliding and one plate is being
subducted beneath another.
Just like earthquakes caused by nature, human-induced earthquakes have the potential
to be dangerous, even deadly.

28. Tsunami

29. Tsunami is a Japanese word which means harbour wave. It is also called the killer sea
wave. It is a large sea wave. Sudden displacement of huge amounts of water in the sea
causes tsunami.
Causes of Tsunami
Following are the causes of Tsunami:
Earthquake: It is the most common cause of tsunami. Earthquake is shaking of
earth. When it happens underwater, the sea floor lifts and drops back down. It
causes displacement of water. This results into huge water waves.
Volcanic Eruption: The collapse of a coastal or underwater volcano can cause a
landslide leading to a tsunami. When the hot lava or magma from collapsing
volcano meets cold sea water, it can create a steam explosion. Which can results
into tsunami waves.
Underwater landslide: Underwater landslides can also displace large amounts of
water. Which can generate tsunamis.
Asteroid Impact: If an asteroid lands into the ocean, it can generate huge tsunami
waves.

30. Landslides

31. Landslides are caused by disturbances in the natural stability of a slope. They can
accompany heavy rains or follow droughts, earthquakes, or volcanic eruptions. Mudslides
develop when water rapidly accumulates in the ground and results in a surge of water-
saturated rock, earth, and debris.
What Causes a Landslide in India?
1. Deforestation. Landslides due to human intervention is one of the causes of landslides
in India
2. Shifting Cultivation. Shifting cultivation is common in hilly regions and Northeast
areas.
3. Heavy Rainfall and Earthquakes
4. Mining
5. Urbanization
The impact of a landslide can be extensive, including loss of life, destruction of
infrastructure, damage to land and loss of natural resources. Landslide material can
also block rivers and increase the risk of floods
There are also various direct methods of preventing landslides; these include modifying
slope geometry, using chemical agents to reinforce slope material, installing structures
such as piles and retaining walls, grouting rock joints and fissures, diverting debris
pathways, and rerouting surface and underwater drainage.

32. Volcanic Eruptions

33. Volcanic eruptions can result in additional threats to health, such as floods, mudslides,
power outages, drinking water contamination, and wildfires
Volcanic eruptions may be subtle or explosive and can produce dangerous lava flows,
poisonous gases, and flying rocks and ash. Many volcanic eruptions are also accompanied
by other natural hazards, such as earthquakes, landslides, debris flows, flash floods, fires
and tsunamis.
The world's largest eruption of the 20th century occurred in 1912 at Novarupta on the
Alaska Peninsula in what is now Katmai National Park and Preserve. An estimated 15
cubic kilometers of magma was explosively erupted during 60 hours beginning on June
6th.
When enough magma builds up in the magma chamber, it forces its way up to the
surface and erupts, often causing volcanic eruptions. In the ocean, volcanoes erupt along
cracks that are opened in the ocean floor by the spreading of two plates called a mid-
ocean ridge
Sixty percent of all active volcanoes occur at the boundaries between tectonic plates.
Most volcanoes are found along a belt, called the “Ring of Fire” that encircles the
Pacific Ocean. Some volcanoes, like those that form the Hawaiian Islands, occur in the
interior of plates at areas called “hot spots.”