Category : Disaster Management
A natural disaster is the consequence or effect of a hazardous event, occurring when human activities and natural phenomenon (a physical event, such as a volcanic eruption, earthquake, landslide etc. that does not affect human beings) become entangled. The resulting fatalities or property damages depend on the capacity of the population to support or resist the disaster (2004). This understanding is crystallized in the formulation: "disasters occur when hazards meet vulnerability” (, 1994).
The archaeological record for natural disasters is a long one, as you might imagine. Over the ocean of human civilization, meaning the last 20,000 years or so, human societies have risen and fallen like the tide. The reasons for the rise of such societies are multiple, as are the reasons for their destruction: attacks from the outside, revolution from the inside, pollution or depletion of necessary resources. These are cultural factors at work, the effects of humans. But, all societies were and are also subject to natural disasters or, as the insurance people would like to say "acts of god."
The sites where the writer gathered the facts for the said report are the web site of the FEMA Disasters Community and an article about natural disasters from the site While the complete facts about the books used are located on the reference part.
The report consists of an introduction to the topic, facts on the different classifications of natural disasters and a concluding part about the said topic.
Natural Disasters: An Overview
Natural disasters can be classified into two. The first one is natural disasters as a result of common natural phenomena. Under this category are the avalanche, blizzards and snowstorms, drought, earthquake, epidemic, famine, flood, forest fire, hailstorm, heat wave, hurricanes, tropical cyclones and typhoons, ice storm, lahar, landslides and mudslides, sinkholes, tornado, and tsunami. The second classification is the extreme natural disasters. Among them are the ice age, impact event, solar flare, super volcano, and mega tsunami. They are further discussed in detail on the latter part.
Natural Disasters as a Result of Common Natural Phenomena
An example of a gravity current consisting of granular material is an avalanche. An avalanche is a geophysical hazard involving a slide of a large snow (or rock) mass down a mountainside. It is caused when a buildup of snow is released down a slope. In here, lots of material or mixtures of different types of material fall or slide rapidly, under the force of gravity. Avalanches are often classified by what they are made of, for example snow, ice, rock or soil avalanches (although these may be called Landslides or Rockfalls). A mixture of these would be called a debris avalanche. Avalanches also one of the major dangers faced in the mountains during winter.
A snowstorm, on the other hand, is a winter storm in which snow is its primary form of precipitation. When such a storm is complemented by winds above 32 mph that severely reduce visibility, it develops into a blizzard. Hazards from snowstorms and blizzards include traffic-related accidents, hypothermia for those unable to find shelter, as well as major disruptions to transportation and fuel and power distribution systems.
A long-lasting weather pattern consisting of dry conditions with very little or no precipitation at all is called drought. Food and water supplies during this period can run low. Or worse, other conditions such as famine can result. Droughts can last for several years. And it is damaging predominantly in areas in which most of the residents depend more on agriculture for their survival. A famous example of a severe drought is the Dust Bowl.
An earthquake is a sudden shift or movement in the tectonic plate of the Earth’s crust. On the surface, this is manifested by a moving and shaking of the ground. This can cause extreme damage to structures which are poorly built. On the other hand, the most powerful earthquakes can destroy even the best built of structures. Besides, they can also trigger secondary disasters, such as tsunamis and volcanic eruptions. Earthquakes occur along fault lines, and are often unpredictable. They are also capable of killing hundreds of thousands of people, such as in the incidence of the 1976 Tangshan, as well as the 2004 Indian Ocean earthquakes.
An epidemic is defined as a massive outbreak and spread of an infectious disease. It is historically, the most dangerous of all natural disasters. Different epidemics are caused by different diseases. Black Death, smallpox, and AIDS are among the prominent ones. The Spanish flu of 1918, on the other hand, was the deadliest ever epidemic. It was responsible for the deaths of over 25-40 million people. The Black Death, which occurred in the fourteenth century, killed over twenty million people, which is one third of Europe’s population.
Famine is a natural disaster depicted by a widespread lack of food in a region. It can also be characterized as a lack of agriculture foodstuffs, a lack of livestock, or a general lack of all foodstuffs which are vital for one’s basic nutrition and survival. Pre-existing conditions such as drought almost always caused this type of disaster. But social factors such as war may aggravate its effects. Particularly devastating examples include the Ethiopian famine and the Irish Potato Famine.
On the other hand, a flood is a natural disaster caused by too much rain or water in a location, and could be caused by many different sets of conditions. Floods can be caused by extended rainfall from a storm, including thunderstorms, rapid melting of large amounts of snow, or rivers which swell from excess precipitation upstream and cause widespread damage to areas downstream, or less frequently the bursting of man-made dams or levees. A river which floods very often is the Huang He River in China, while a particularly damaging flood was the Great Flood of 1931.
A natural disaster consisting of a fire which destroys a forested area is called a forest fire. It can be a great danger to people who live in forests as well as wildlife. Forest fires are generally started by lightning, but also by human negligence or arson, and can burn thousands of square kilometers. An example of a severe forest fire is the Oakland Hills firestorm.
A hailstorm, on the other hand, is a natural disaster where numerous hailstones, which damage the location in which they fall, are produced by a thunderstorm. Hailstorms can be destructive to farm fields, crops and equipment, in particular. A remarkably damaging hailstorm is the one which hit Munich, Germany on August 31, 1986, felling thousands of trees and causing millions of dollars in insurance claims.
A heat wave is a disaster characterized by an extreme and unusual heat in the area in which it occurs. Heat waves are rare and require specific combinations of weather events to take place. It may include temperature inversions, katabatic winds, or other phenomena. The worst heat wave in recent history was the European Heat Wave of 2003.
Hurricane, tropical cyclone, and typhoon are different names for the same phenomenon: a cyclonic storm system that forms over the oceans. It is caused by evaporated water that comes off of the ocean and becomes a storm. The Coriolis Effect causes the storms to spin. And when this spinning mass of storms attains a wind speed greater than 74 mph, a hurricane is already declared. In the Atlantic Ocean, hurricane is used for these phenomena while it is called a tropical cyclone in the Indian. For the eastern Pacific, it is typhoon whereas in the vicinity of Oceania, it is Willy Willies. The deadliest hurricane ever was the 1970 Bhola cyclone, at the same time as the Great Hurricane of 1780 was the deadliest hurricane in the Atlantic region. It is known to ravaged Martinique, St. Eustatius and Barbados.
An ice storm is a particular weather event in which precipitation falls as rain, due to atmosphere conditions. It happens only in an area in which the temperature is below the freezing point of water. The rain falls to the ground, and immediately turns to ice, accumulating in that fashion. A heavy ice storm can cause large accumulations of ice, which in turn can cause trees to fall over or lose branches, and power lines to snap. The worst recent ice storm was the 1998 Ice Storm that struck eastern Canada and areas of the US northeast.
A lahar is a type of natural disaster closely related to a volcanic eruption. It involves a large amount of material; including mud, rock, and ash sliding down the side of the volcano at a rapid pace. Entire towns can be destroyed and thousands of people can be killed by these flows, just in seconds. An excellent example is the Tangiwai disaster, as it killed an estimated twenty three thousand people in Armero, Colombia, during the 1985 eruption of Nevado del Ruiz.
A landslide, on the other hand, is a disaster closely related to an avalanche. But instead of snow, it occurs involving actual elements of the ground, including rocks, trees, and parts of houses, anything else which may happen to be swept up. Landslides can be caused by earthquakes, volcanic eruptions, or general instability in the surrounding land. A special case of landslides includes mudslides or mud flows. In here, heavy rainfall causes loose soil on steep terrain to collapse and slide downwards. These occur with some regularity in parts of California after periods of heavy rain.
Sinkholes are localized depression in the surface topography, usually caused by the collapse of a subterranean structure, such as a cave. Although rare, large sinkholes that develop suddenly in populated areas can lead to the collapse of buildings and other structures.
A tornado is a natural disaster resulting from a thunderstorm. Tornadoes are violent, rotating columns of air which can blow at speeds between fifty and three hundred mph, and possibly higher. Tornadoes can occur one at a time, or can occur in large tornado outbreaks along squall lines or in other large areas of thunderstorm development. The most violent tornado ever recorded in terms of wind speed was the tornado which swept through Moore, Oklahoma on May 3, 1999. This tornado has wind speeds of three hundred eighteen mph measured by mobile doppler radar devices.
Finally, a tsunami is a giant wave of water which rolls into the shore of an area with a height of over 15 m (50 ft). It comes from the Japanese words "津波" meaning harbor and wave. Tsunami can be caused by undersea earthquakes as in the 2004 Indian Ocean Earthquake, or by landslides such as the one which occurred at Lituya Bay, Alaska. The tsunami generated by the 2004 Indian Ocean Earthquake currently ranks as the deadliest tsunami in recorded history. The highest Tsunami ever recorded was estimated to be 85m (278 ft.) high. It appeared on April 24th, 1771, off Ishigaki Island, Japan.
Extreme natural disasters
An ice age is a geologic period. But, it could also be viewed in the light of a catastrophic natural disaster, since in an ice age, the climate all over the world would change and places which were once considered habitable would then be too cold to permanently inhabit. A side effect of an ice age could possibly be a famine, caused by a worldwide drought.
An impact event is a natural disaster in which an extraterrestrial piece of rock or other material collides with the Earth. The exact consequences of a direct Earth impact would vary greatly with size of the colliding object, although in cases of medium to large impacts short-term climate change and a general failure of agriculture. An example would be the Tunguska event.
A solar flare on the other hand, is a phenomenon where the sun suddenly releases a great amount of solar radiation, much more than normal. It is theorized that these releases of radiation could cause a widespread failure of communications technology across the globe. The exact implications of such a failure are unknown. Further studies are being carried out.
A super volcano is an eruption which is considered to be thousands of times more massive than a normal eruption. If a volcano expels at least a thousand cubic kilometers of material, it is already declared as a super volcano. The last eruption of this magnitude occurred over 75,000 years ago at the Lake Toba. If such an eruption were to occur today, a wholesale general die-off of both animals and humans would occur, as well as a significant short-term climate change.
And lastly, a mega tsunami is a term used to describe very large tsunamis, by the popular media. They are a highly local effect, either occurring on shores extremely close to the origin of a tsunami, or in deep, narrow inlets. The largest waves are caused by a very large landslide, such as a collapsing island, into a body of water. They can potentially reach twenty km inland in low-lying regions.
How are we affected by natural disasters?
Natural disasters can bring about high death tolls. One proof is the record of a total of 158,551 deaths associated with earthquakes around the world between the years 1980-2000 (Source: ). For the tropical cyclone related deaths, it has a record of 251,384 total deaths worldwide, for the same years. For floods, it was 170,010 deaths.
But, it is not the only effect of natural disasters to us. Annual economic losses are also associated with such disasters, which averaged to US$ 659.9 billion in the year 1990s. Also, eighty five percent of the people exposed to such disasters live in countries having either medium or low human development.
Water-related hazards affect millions of people, putting human security at risk and slowing down socioeconomic activities. These are major features of natural disasters worldwide. At almost any point in time, a hazard is threatening communities in terms of both the lives of the inhabitants and their properties. Few of these events are reported in the international media due to their relatively small impact. However, events like floods in Bangladesh and Haiti and, tsunami in Asia during 2004 drew significant international attention.
According to the Intergovernmental Panel on Climate Change (IPCC), the trend is probably leading to worse scenarios, as the magnitude and frequency of floods and droughts might increase during the twenty first century due to climate change. Other factors, such as population growth, increased wealth, demographic shifts, and changes in land use and the value of various goods might also result in an increased level of damage and loss of life associated with water-related disasters.
The destruction of infrastructure, the erosion of livelihoods, damage to the integrity of ecosystems and architectural heritage, injury, illness and death are direct outcomes of disaster. But disaster losses interact with and can also aggravate other stresses and shocks such as a financial crisis, a political or social conflict, disease (especially HIV/AIDS), and environmental degradation. And such disaster losses may set back social investments aiming on ameliorating poverty and hunger, provide access to education, health services, safe housing, drinking water and sanitation, or to protect the environment as well as economic investments that provide employment and income.
Natural disaster has a tremendous effect not only physically but also on the mental aspects of an individual especially the younger ones.
Losses due to natural and man-made disasters will continue to increase because of our continuing population growth and the increase of the concentration of growth in vulnerable areas such as coastal regions, flood plains, and seismically active zones. As a result, more lives will be lost, more property will be destroyed, and the social and economic fabric of disaster-prone communities will be disrupted. But this does not have to be so. The global scope of disasters requires that we coordinate our efforts for their mitigation on an international basis. Advances in the science and technology of hazard mitigation now provide the means to reduce significantly losses from natural hazards. But we have to commit ourselves to understanding these hazards better and to applying techniques that reduce our vulnerability. We need to explore the feasibility of concerted scientific and engineering efforts in reducing the loss of life and property through programs of public education and of effective early warning systems. The development of early warning systems with an adequate array of monitoring instruments for the purpose of collecting necessary data and information for disaster evaluation, is necessary for establishing relative potential risks. Public educational efforts and rapid communication networks are needed for transmitting information on potential disaster risks and for warning purposes in order to save lives and minimize damage to property.
The time has come to bring the full force of scientific and technological advances to the reduction of human tragedy and economic losses from natural and man-made disasters. We must take an integrated approach to disaster reduction, bringing new emphasis to research on disasters, on pre-disaster planning, on preparedness, and on disaster prevention, while we sustain our post-disaster relief capabilities. Our humanitarian efforts must be broadened to include disaster education and preparedness of the public as well as early warning systems in which people at risk receive, understand, and act upon the warning information conveyed.