Disasters are truly catastrophic. Defined as a sudden accident that causes great damage or loss of life they have caused lot of damage to humanity throughout the beginning of world.
A natural disaster is a major adverse event resulting from natural processes of the Earth Earlier people used to think that disaster occurred because human activities made gods angry and the gods released their wrath upon them.
But now we have geologists working that have explanations for the reasons behind natural disasters.
Some disasters arrive without warning, leaving survival to luck.
Often, however, there is a small window of time giving people a chance to escape.
Let’s take a look at some of the major natural disaster that we should be familiarize with.
#1 Avalanches and land slides
Landslides and avalanches are both examples of natural geological disasters.
A landslide is the outward and downward movement of numerous materials like earth and debris on a wet slippery surface.
Landslides can also take place underwater (submarine landslide), and in coastal environments.
Although gravity is the vital driving force of landslides, there are many other factors like deforestation which affect the stability of the slopes.
What is an avalanche?
It’s a large mass of snow and ice or of earth or rock sliding down a mountain side or a cliff.
And how does an avalanche occur?
Well mainly they happen by vibrations caused by movement of the earth such as an earthquake, gunfire, rainy weather, and many more.
Avalanches occur in mountainous regions with a thick snow cover while a landslide occurs in sloppy places with loose and muddy soil.
#2 Earthquakes
An earthquake is the shaking of the surface of the Earth resulting from a sudden release of energy in the Earth's lithosphere that creates seismic waves (wave of energy that travel through earth’s layer).
What is lithosphere?
The lithosphere is the rocky outer part of the Earth.It is made up of the brittle crust and the top part of the upper mantle.The lithosphere is the coolest and most rigid part of the Earth.
Earthquakes can range in size from those that are so weak that they cannot be felt to those violent enough to propel objects and people into the air, and wreak destruction across entire cities.
The seismicity, or seismic activity, of an area is the frequency, type, and size of earthquakes experienced over a period of time.
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The earth has four major layers: the inner core, outer core, mantle and crust.
The crust and the top of the mantle make up a thin skin on the surface of our planet.
But this skin is not all in one piece – it is made up of many pieces like a puzzle covering the surface of the earth.
Not only that, but these puzzle pieces keep slowly moving around, sliding past one another and bumping into each other.
We call these puzzle pieces tectonic plates, and the edges of the plates are called the plate boundaries.
This non-stop movement of tectonic plates causes stress on Earth’s crust.
When the stresses get too large, it leads to cracks called faults.
When tectonic plates move, it also causes movements at the faults.
An earthquake is the sudden movement of Earth’s crust at a fault line.
The location where an earthquake begins is called the epicenter.
An earthquake’s most intense shaking is often felt near the epicenter.
However, the vibrations from an earthquake can still be felt and detected hundreds, or even thousands of miles away from the epicenter.
#3 Volcanic eruptions
A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface.
Deep within the Earth it is so hot that some rocks slowly melt and become a thick flowing substance called magma.
Since it is lighter than the solid rock around it, magma rises and collects in magma chambers.
Eventually, some of the magma pushes through vents and fissures to the Earth's surface.
Magma that has erupted is called lava.
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Some volcanic eruptions are explosive and others are not.
There are two types of eruptions in terms of activity, explosive eruptions and effusive eruptions.
Explosive eruptions are characterized by gas-driven explosions that propels magma and tephra.
Effusive eruptions, meanwhile, are characterized by the outpouring of lava without significant explosive eruption.
Erupting volcanoes can pose many hazards, not only in the immediate vicinity of the eruption.
One such hazard is that volcanic ash can be a threat to aircraft, in particular those with jet engines where ash particles can be melted by the high operating temperature.
The melted particles then adhere to the turbine blades and alter their shape, disrupting the operation of the turbine.
Large eruptions can affect temperature as ash and droplets of sulfuric acid obscure the sun and cool the Earth's lower atmosphere (or troposphere).
However, they also absorb heat radiated from the Earth, thereby warming the upper atmosphere (or stratosphere).
#4 Floods
Flooding is an overflowing of water onto land that is normally dry.
Floods can happen during heavy rains, when ocean waves come on shore, when snow melts too fast, or when dams or levees break.
Flooding may happen with only a few inches of water, or it may cover a house to the rooftop.
A flood is an overflow of water that submerges land that is usually dry.
In the sense of "flowing water", the word may also be applied to the inflow of the tide.
Floods are an area of study of the discipline hydrology and are of significant concern in agriculture, civil engineering and public health.
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Flooding may occur as an overflow of water from water bodies, such as a river, lake, or ocean, in which the water overtops or breaks levees.
A levee is an elongated naturally occurring ridge or artificially constructed wall that regulates water levels.
Resulting in some of that water escaping its usual boundaries, or it may occur due to an accumulation of rainwater on saturated ground in an areal flood.
While the size of a lake or other body of water will vary with seasonal changes in precipitation and snow melt, these changes in size are unlikely to be considered significant unless they flood property or drown domestic animals.
Some floods develop slowly, while others can develop in just a few minutes and without visible signs of rain.
Additionally, floods can be local, impacting a neighborhood or community, or very large, affecting entire river basins.
#5 Hailstorms
Any thunderstorm which produces hail that reaches the ground is known as a hailstorm.
Hail has a diameter of 5 millimeters or more.
Hailstones can grow to 15 centimeters and weigh more than 0.5 kilograms.
Unlike ice pellets, hailstones are layered and can be irregular and clumped together.
Hail is a type of precipitation, or water in the atmosphere.
Hail is formed when drops of water freeze together in the cold upper regions of thunderstorm clouds.
These chunks of ice are called hailstones.
Most hailstones measure between 5 millimeters and 15 centimeters in diameter, and can be round or jagged.
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Hailstones are not frozen raindrops.
Frozen rain falls as water and freezes as it nears the ground.
Hail actually falls as a solid.
Hailstones are formed by layers of water attaching and freezing in a large cloud.
A frozen droplet begins to fall from a cloud during a storm, but is pushed back up into the cloud by a strong updraft of wind.
When the hailstone is lifted, it hits liquid water droplets.
Those droplets then freeze to the hailstone, adding another layer to it.
The hailstone eventually falls to Earth when it becomes too heavy to remain in the cloud, or when the updraft stops or slows down.
Hail can be transparent (clear) or translucent (cloudy).
Hailstones can cause extreme damage to buildings, vehicles, and crops.
Not surprisingly, people have tried to find ways to prevent hail.
In the 18th century, Europeans began trying to prevent hail by firing cannons into clouds and ringing church bells.
In the 20th century, Russia and the United States tried cloud seeding.
Cloud seeding is adding chemical particles into clouds from rockets or aircraft.
It is thought to control rain and hail.
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