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Does human activity affect the impact of a natural disaster ?

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David Cleasby

on 26 September 2012

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Transcript of Does human activity affect the impact of a natural disaster ?

Does human activity affect the impact of a natural disaster ?
A hazard is phenomenon which can cause loss of life, injury, disease, economic loss, or environmental damage. SO what is a hazard? Hazards are linked with disasters, which is an event that causes great loss of life, injury or damage and loss of property.  Which is nicely summed up this diagram. Its the variety within the vulnerability and the extent of the natural hazard that decides how much of a risk the hazard will be. However as a race are we causing a bigger impact than necessary ? This will be assessed by looking at three different hazards. Flooding - Flooding affects more people across the globe per year compared to volcanoes and earthquakes simply because flooding can occur across most areas of land whereas volcanic activity and earthquakes occur near plate boundaries.

-However flooding occurs more in areas of flat, level lands for example high rates of flooding in South East Asia (due to monsoon rains) compared to flooding in mountainous areas.

- Floods account for 15 percent of worldwide deaths and affect, on average, up to 500million people per year. Although the risks are quite apparent, why do people live in this area ? Job opportunities.
River sediments from deposition provides fertile soil for agriculture.
Flood-plains usually have flowing rivers, which can be used as a form of transportation and/or leisure activities.
Reliable source of food (ie fish) and water.
Flat land around rivers lends itself to development.
Friends and family live in the same area.
Many people have lived in these areas all their lives and think nothing will happen to them during their lifetime. Case Study New Orleans After Hurricane Katrina in 2005. 80% of the city flooded and was overcome as flood water lingered for weeks after. Total property damage came to around $81billion. However, after such destruction, the City of New Orleans was rebuilt on the floodplain. This becomes dangerous because people who build in a flood plains are not guaranteed to have flood insurance and therefore are putting the lenders finance at risk of future hazards.

Levee’s in the area surrounding New Orleans were highly relied on during the 2005 Hurricane, however these defence mechanism’s failed to protect the areas causing greater damage to the city this is an example of how human actions can turn a natural hazard into a disaster. Throughout the rebuilding of New Orleans, Levee’s were again put in place as Defensive techniques even though they failed to protect the city the first time, making them a liability to future natural hazards.

Following the devastating impacts from flooding in New Orleans, many people still fail to insure their homes and land, this is mainly due to it being too expensive, or their belief that it won’t happen again in their lifetime. How do Humans increase their vulnerability to flooding ? Urbanisation- Building vast cities means large areas of ground are built upon and can no longer absorb water therefore during heavy rain fall the water will linger on the surface and increase the risk of flooding.

Population Growth- With a growth in population more land is needed for urbanisation, and houses/buildings are being built on previously unused ground, such as floodplains, increasing the flood risk.

Population Density- The more people that live in an area, the greater the effects of a disaster.

Global Warming- With Rising temperatures and sea levels the risk of coastal flooding is increasing.

Lack of defences- Defences such as levees, sea walls, dams, flood barriers, or even cheap alternatives such as mangroves planting can all be used but may not be if they are seen as too expensive, therefore their risk of flooding remains high. Volcanoes Why do people live in Volcanic areas?
Generally the advantages outweigh the disadvantages, most dormant volcanoes are safe for long periods and those which erupt frequently are genuinely thought of as predictable

3 types of people:
- Fatalists take the pros outweighing cons approach
- Adaptionists: stay at the locations in order to try and improve the area

- Fear: people who run away and wont live in a hazard zone Minerals
- When magma rises and cools it contains a range of minerals and are precipitated due to the movement of superheated water and gases through the rock.
- Minerals precipitated at different locations and include different minerals e.g. gold
-Hot gases which escape via the vents to the surface (sulphur) condenses and solidifies locals will sell as sulphur Fertile soils
- Volcanic rocks rich in minerals
- rocks need thousands of years to become weathered and broken down
- e.g. Naples Italy, area intensely cultivated and produces a variety of vegetation due to the Vesuviusius eruption years prior Geothermal energy
- Heat energy from the earth is used to heat the underground and drive turbines producing water and electricity supplies
- Steam not used directly as too many dissolved minerals (poisionous water supply)
- e.g. Iceland uses their own geothermal water supply Tourism
- Impressive natural wonders attract a wide range of tourism
-features such as bathing lakes, hot springs, mud pools and geysers
- Iceland: attracts much tourism as a result of its fire and ice – combination of volcanoes and glaciers
- also help with a countries income e.g. Uganda an LEDC relies on tourism in volcanic region for its landscapes wildlife etc. To some extent the devastation of a volcanic hazard does lie within people’s hands this is due to the nature of vulcanicity, such as its unpredictability, lack of knowledge as well as radius to eruption.

However on the other hand the hazards of volcanic activity is more well known people are more aware of the effects fatalists for example would choose to ignore the dangers and believe the pros outweighs the cons, and with growing population figures globally it is causing more people to reside in these hazard danger zones making the devastation more imminent when it occurs.

Essentially whether people are responsible for volcanic hazards merely depends on the location, predictability as well as knowledge regarding the activity. Do we exacerbate the effects of the hazard ? and why do we continue to live there despite knowing the apparent risk ? Earthquakes The vast majority of earthquakes all occur on or close to the plate boundaries, which make the rocky crust of the earth, known as the lithosphere, the map highlights this. Due to earthquakes being mostly a natural occurrence its hard for humans to interfere and have an impact upon the severity of the earthquake In this instance its more social factors that play the part in the impact of the hazard, some people are more vulnerable than others particularly in LEDC countries such as Haiti, this is down to

- Poor infrastructure
- Dense population

However we also increase the vulnerability of people by building structures that could potentially have fatal consequences such as a nuclear facility, this is partly why the Japanese quake of 2011 was so devastating. However There has been some instances of humans contributing to earthquakes with actions such as underground explosions, the creation of dams and also there's evidence that the process of fracking can contribute to earthquakes. Overall as humans we create a bigger impact than needed due to the social situation of the some of the countries that get impacted upon, however earthquakes are very powerful hazards and quite frankly sometimes there's nothing we can do to prevent them. This can be highlighted by the 2010 Chilean earthquake that moved the earths axis by 3". Conclusion Human activity can have a detrimental impact upon the severity of a hazard, however it all depends on the hazard, we have more control of some then others. Its seems quite clear that humans have had an impact upon the severity of hazards, which then leads to the question. As humans do we have the right to interfere or do we have an obligation to protect the world for the generations to come ?
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