Natural Disasters: Types, Causes and Consequences

Umme Kulsum Eti

Natural Disasters: Types, Causes and Consequences

Natural disaster is an unforeseen occurrence of an event that causes harm to society. There are many natural disasters that damage the environment and the people living in it. Spatial extent measures the degree or severity of the disaster. Disaster causes great suffering for the people during the disaster period and   after the period of   disaster.

It is a long  time process of  vulnerability. Natural disaster is a  natural event such as  flood, earthquake, or  hurricane that causes  great damage or loss  of life. [1] It is a   catastrophic events  with atmospheric,  geological and hydrological origins.  

Sylvia Mathews Burwell, US Secretary of Health and Human Services said, “While natural  disaster captures headline and national attention short- term, the work of recovers and rebuilding  is long term.” [2]

According to world Health Organization — “A natural disaster is an act of nature of such magnitude as to create a catastrophic situation in which the day- today patterns of life suddenly disrupted and people are plunged into helplessness and suffering, and as a result need food, clothing, shelter, medical and nursing care and other necessities of life and protection against unfavorable environmental factors and condition.” [3]

Neil de grass Tyson, The American anthropology, said “Even with all our Technology and the Inventions that make modern life so much easier than it once was, it takes just one big natural disaster to wipe all that away and remind us that Hero on earth we are still at the mercy of nature.” [4]

Examples of some major natural disasters— There are some major natural disaster that have a  great impact on human and environment are given in the following discussion— 


It is a natural event or occurrence where a piece of land or area that is usually dry land, suddenly get submerged under water. Sometimes flood occurs suddenly and regresses quickly. It can damage houses, bridge, furniture, even people. The causes of flood are urban drainage basins, storm surges and tsunamis, melting snow and ice. [5] 

Flood distributes and deposits river sediments over large area of land. Coastal flooding is caused by weather and high tides that can make rise in  sea levels. River bursts its banks typically due to high rainfall over  a period of time and causes river flooding.  

Heavy rainfall also can make  flooding. As a result of a blockage  or failure of drainage system, there  can be a flooding situation .In the  UK, there is a national move away  from flood defense to flood risk  management and enabling  communities to take reasonable  responsibility to protect their home  work place.  

Earthquake: The shaking of  the surface of the earth resulting  from a sudden release of energy in  the earth`s lithosphere that creates a seismic waves is called earthquake. 

At the earth surface, earthquakes manifest themselves by shaking and displacing or disrupting the  ground. When the epicenter of a large earthquake is located offshore, the seabed may be displayed  sufficiently to causes a Tsunami It can also Trigger land sides and occasionally volcanic  activities.[6] 

Earthquakes are not only caused by rapture of geological faults but also by other events such as  volcanic activities, land sides, mine blast and nuclear tests. The point of initial rapture is called its  focus/hypocenter.  


Cyclone, tropical cyclone, hurricane and typhoon are different names for the same phenomenon. The term  is based on its originate. Commonly, hurricanes are massive systems that form over warm ocean waters  move toward land. It is a tropical cyclone with winds of 74 miles (119 kilometer) per hour or greater that  occurs especially in Western Atlantic that is usually accompanied by rain, thunder and lightning.[7] The  word hurricane is derived from the Spanish word huracn, the origin of which is the Caribe term for (God of Evil) .Other sources however  postulate that the word is derived from the  name of the Mayan Storm God  hurricane. [8] 

Warm ocean water is the fuel of  hurricanes. Wind is a major element of hurricanes. Hurricanes form because of  differences between zones of high and  low pressure. Hurricane begin as  Tropical Storms over the warm moist  waters of the Atlantic and Pacific  oceans near the Ecuador. Near the  Philippines and the China Sea  hurricanes are called Typhoons.

The  Atlantic coast, the Gulf of Mexico, the Hawaiian Islands are the most vulnerable to Hurricane. Of the 36  hurricanes, 11 have directly hit Florida making it the state with most direct hits from hurricanes in the US  according to the information from the national Hurricane Centre.  

When a Hurricane strikes a coastal area, it’s brings a number of serious hazards. These hazards include  heavy rains, high winds, a storm surge, even tornados. Heavy rain causes flooding in inland places. Some  of the stronger storm can produce 100mph winds, uprooting trees, beachfront houses demolished. [9] 


Drought is an example of natural disaster that builds  over time. It is defined as an extended period in  which available water is insufficient for human and  agricultural needs. Draught affects production and  human society, so they are considered as disaster of  natural, supernatural or human causes. Land and water temperatures, air circulation and  weather patterns, soil moisture level also contribute  to drought. It can be a supply and demand of water  issue. Examples of drought impact on society  include anxiety or depression about economic loses  and conflicts when there is lack of enough water,  reduced income, higher incident of heat stroke even  loss of life. It can also provide a substantial increases  in wild life risk.[10]


A Tsunami is a series of waves caused by earthquakes or under sea volcanic eruption. But in the depth of  the ocean Tsunami waves don’t dramatically increase in height. But as the waves travel inland, they build  up to higher and higher heights as the depth of the ocean decreases. It occurs most often in Pacific Ocean  and Indonesia because the Pacific Rim bordering the ocean has a number of active  submarine earthquake zones. Recently  occurred in Mediterranean sea Indian  Ocean earthquake and Tsunami killed 22, 7898 people of 14 countries. Banda Aceh of Indonesia, the largest number victim.[11] 

Local Tsunami originates from within  about hundred kilometer less than 1 hour Tsunami travel time from the impacted  coastline. Regional Tsunami is the 1000  kilometer from its source arrive to affected  coastline 1-3 hours. Tele/ ocean wide/  distant is 1000 kilometer and 3 hours  Tsunami.  


It occurs when masses of rock, earth on debris move down a slope. Erosion caused by sporadic running  water such as streams, rivers, winds, currents, ice and waves wipes out latent and lateral slope support  enabling landslides to occur  easily. It destroys  infrastructure, damages  pipe and electronic loans  and communication lines  are particularly vulnerable  as they have little  foundation. 


It is a rapid flow of snow  down a hill or mountainside.  In mountainous terrain,  avalanches are among the  most serious object natural  hazards to life and property  with their destructive  power. Slab avalanches  are the most dangerous type  of avalanche. Humans  trigger 90% of avalanche  disasters, with as many as  40 death in North America  each year. [12] 


It is simply an uncontrolled fire that is weeping about large field and areas of land .Australia is being  ravaged by the wildfire seen in in decades. It can be classified as bushfire, brush fire, grass fire, peat  fire.85%of wildfire in USA are caused by humans. 

Reference health emergencies/natural events/en 


5.ohnaka.M.(2013).The Physics of Rock Failure and Earthquakes-Cambrige University,press.p.148 6. of the word hurricane 

8. damage 





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