Discuss the degree to which the theory of plate tectonics is supported by seismic and volcanic activity
Discuss the degree to which the theory of plate tectonics is supported by seismic and volcanic activity. The theory of plate tectonics suggests that the earth's lithosphere is split into plates (as shown in map 1). At their boundaries the plates submerge, diverge and slide past one another, this movement is caused by convection currents in the asthenosphere. The idea that the plates are moving is not new, as early as 1620 the English philosopher Francis Bacon was aware that the continents seemed to fit together. In 1912 Wegener suggested that the continents were once joined as the super continent Pangaea (as seen in image 4) and that they had drifted apart, he gathered a large amount of evidence to support this theory. Continents appear to fit together, more significantly so if continental shelves are taken to be the true edges of the land mass. There is a vast array of geological evidence that includes similar glacial deposits being found in Antarctica, S. America and India. Antarctica, Svalbard, N. America and the UK all contain coal deposits of a similar age that were formed in tropical conditions, they are no longer in tropical climate zones. Biological evidence is also available, Marsupials are only found in Australia because the predator that wiped them out elsewhere had not migrated there before it drifted away from the main super continent. Despite this evidence,
Cholera - its global impact
Cholera Cholera is an infectious disease caused by the bacterium Vibrio cholera, which usually spreads through contaminated water. It affects the absorption of water in the small intestine and in severe cases produces severe diarrhoea. The most dangerous aspect of Cholera is the immense loss of fluid that can occur within a few days. Without treatment within 24 hours of developing the disease, the loss of fluid can be fatal. Many cases, such as those in Zimbabwe, require hospitalisation of infected people so that fluids can be administered straight into the bloodstream with the use of a drip. Cholera bacteria occur naturally in coastal waters, where they attach to tiny crustaceans called Copepods. The Cholera bacteria travel with the Copepods, spreading worldwide as the crustaceans follow their food sources, which are certain types of algae and plankton. These grow rapidly when the water temperatures rise and algae growth is further increased by the urea found in sewage and agricultural runoff. Therefore most Cholera outbreaks occur in spring and autumn when ocean surface temperatures and algae blooms are at their highest. More algae mean more Copepods, and more Copepods mean more Cholera bacteria. The map on the left shows that the areas that Cholera is discovered in are situated below the Brandt line. This is because these areas are surrounded by warm oceans where the
The number of fatalities that result from volcanic and seismic natural hazards is related to the level of development in the country in which they occur. Discuss.
The number of fatalities that result from volcanic and seismic natural hazards is related to the level of development in the country in which they occur. Discuss. A natural hazard is an event, linked to the physical environment, which is considered to have a negative effect on humans. The event is also seen to be unpreventable by humans. However, an event such as a volcanic eruption that has no effect on human beings is considered a natural phenomenon rather than a natural hazard. It is the presence of humans, in an area that such an event occurs, that allows it to be termed a hazard. Although humans cannot prevent these occurrences, they have a role to play in the event's extremity as a natural hazard. For example, volcanic eruptions have been present throughout history, but it is not until settlements are built on the rich soils they form that they become a hazard. This essay I will evaluate the extent to which the level of development in a country affects the number of fatalities caused by volcanic and seismic natural hazards. A volcanic natural hazard is a volcanic eruption. Volcanoes are formed at convergent and divergent plate boundaries and also at hot spots. At convergent plate boundaries eruptions tend to be from a vent, as oceanic crust is forced beneath another plate, the extremities of heat and pressure leads to the partial melting of the crust which is being
In December's tsunami in the Indian Ocean, an estimated 250,000-300,000 people were killed or are still missing, while millions of lives have been upturned, socially and economically, by its impact. A main reason for the huge death
Why are some hazards easier to predict then others? For my essay I will looking at different case studies and reasons why it appears that some hazards are easier to predict then others. There were 497 reported natural hazards that took a significant human toll - between 1974 and 1978. The last five years have seen 1,897 of them, a nearly three fold increase. Between 1974 and 1978, 195 million people were killed by such disasters or needed emergency aid; there were 1.5 billion such victims in the past five years. Natural hazards are happening more often, and having an ever more dramatic impact on the world in terms of both their human and economic costs. While the number of lives lost has declined in the past 20 years - 800,000 people died from natural disasters in the 1990s, compared with 2 million in the 1970s - the number of people affected has risen. Over the past decade, the total affected by natural hazards has tripled to 2 billion. According to wordnet.princeton.edu/perl/webwn a hazard is: - a source of danger; a possibility of incurring loss or misfortune. Predict is defined as:-The skill of explaining new events based on observations or information. According to: - www.dpi.state.wi.us/standards/sciglos.html When looking at the different types of hazards to injure or kill people, or costing the most economic price, we consider such hazards as tsunamis and
Volcanic & Seismic events are pieces of evidence proving that the plate tectonics theory is valid
Volcanic & Seismic events are pieces of evidence proving that the plate tectonics theory is valid The plate tectonics theory was put forward by Alfred Wegener suggesting that the continents were at one point all conjoined in one supercontinent known as Pangaea. He then suggested that Pangaea had drifted apart through the movement of plates to give us the current position of continents we have today. Wegener's theory was linked to a variety of evidence, however it took further research and evidence for this to become a leading theory. This means that although volcanic and seismic events help to prove the plate tectonics theory valid, there is also a range of other factors involved. Vulcanicity is the surface presence of Magma within the Earth's crust. Whereas seismicity is where the build up of pressure in the crust is released. Both volcanic and seismic activty when plotted on a map can be seen to follow certain patterns and it is this distribution that helps explain the plate theory. The distributions of earthquake events are found in broad, uneven belts around plate margins and it is the movement of the plates that cause the seismic events. Most of these earthquakes occur along destructive margins, where the heavier oceanic crust descends underneath continental crust. A build up of pressure here, where no subduction takes place for a space of time, eventually leads to a
Discuss the view that poverty is the real killer in earthquake disasters
Discuss the view that poverty is the real killer in earthquake disasters. (40 marks) Seismic events prove that it is a problematic for the world's population and produce devastating effects on the lives of everyone involved. However it is often said that LEDCs suffer much more from the effects of earthquakes than MEDCs. Whilst this is a generalisation it is probably true, at least in terms of the human cost. Poverty is the condition of lacking basic human needs such as nutrition, clean water, health care, clothing, and shelter because of the inability to afford them. There are several levels of poverty from an individual to national level and earthquake disasters impact at all levels. The 2010 Haiti earthquake struck in the most densely populated area of the country, As More than 78% per cent of Haitian residents live in poverty and Haiti is the poorest country in the Western Hemisphere the buildings in Port-Au-Prince and other areas of Haiti were in very poor condition in general and were not designed or constructed to be earthquake resistant. The primary earthquake hazard directly responsible for mortality is surface seismic waves which cause ground shaking. This poses a huge hazard as buildings and other structures collapse, killing or injuring their occupants. This was the case in Sichuan, China in 2008 where severe ground shaking was the direct cause of death, injury
Explain the increasing frequency of Hydro-meteorological Hazards.
B. Explain the increasing frequency of Hydro-meteorological Hazards. Hydro-Meteorological hazards result from atmospheric or hydrological processes; they are caused by the movement of water in some shape or form, and by weather patterns. Examples can include floods, droughts, hurricanes, tornadoes, storms, blizzards and more. They are natural hazards, which mean they can rarely be predicted, and they also not be controlled or stopped by humans, this can result in more severe damage. By the year 2100, the global mean temperature is expected to have risen from 2.5F to 10.4F (1.4-5.8C) since 1900. This is mainly due to global warming, and the increasing pressure the human race is placing on our planet. One major consequence of this rise in temperature is a rise in erratic weather patterns, which appears to have already begun. There is no official data for the total death toll related to natural hazards from all over the world, only for those events, which are large enough, and reach the destruction scale of a 'disaster'. Total death tolls vary from year to year, there is an average of fewer that 100,000 deaths recorded, this is 30 times fewer than the total number of people who die from HIV or AIDS, and also 50 times less than the number of smoking-related deaths, however, it has to be taken into account that, this total figure is only taken from the Natural hazards, which
The hazards presented by volcanic activity have the greatest impact on the poorest members of the worlds population. To what extent do you agree with this view?
The hazards presented by volcanic activity have the greatest impact on the poorest members of the world's population. To what extent do you agree with this view? Volcanic hazards include the primary effects of lava, lahars, and pyroclastic flows as well as the respiratory issues caused by inhalation of ash and gas. Larger, more ashy eruptions can cause worldwide effects, modern day eruptions halting and diverting commercial flights, but also causing temporary climate change and potential famines. Volcanic activity occurs in developed and undeveloped areas of the world, dictated by plate boundaries and weaknesses that produce hotspots, such as the Pacific Ring of Fire and Hawaii. Despite this, poorer populations such as those in Indonesia receive high frequencies of volcanic activity that may shrink their economies and make repair and development more difficult, potentially implementing a vicious cycle of social and economic problems caused by poor housing and transport preventing the population from working to repair its economy. The eruptions of Soufriere Hills beginning in 1995 affected Montserrat's rich and poor inhabitants. As the mostly uninhabitable island's capital town Plymouth was covered in ash, lahars, and pyroclastic flows, many people were evacuated and the majority of the island's homes were destroyed, displacing 7000 people. As a British territory, residents
The extent to which volcanic processes represent hazards depends on where and when they occur.
'The extent to which volcanic processes represent hazards depends on where and when they occur'. Discuss this statement. A hazard can best be defined as a 'situation that poses a level of threat to life, health, property or the environment.' The overall impact of volcanoes as a natural hazard varies greatly from one place and timeframe to another. Vulcanicity is normally associated with plate tectonic processes and is mainly located along plate margins. Different plate margins known as constructive and destructive on volcanic eruptions and landforms have different effect. Volcanic activity that occurs at a destructive plate margins such as in Mount Merapi & Mount St. Helens eruption potentially could be an explosive volcanoes which are hazardous but both location have different vulnerability impact to the populace. Volcanic processes can be found along oceanic ridges where the plates are moving apart known as constructive plate margins. Volcanic eruption that occurs on a constructive plate margins usually little violence, but the volcanic gases easily escape. Volcanic Hawaiian Islands that are not connected with any plate boundary is an active volcano, but it's not as hazardous due to the plume of magma only rises to eat into the plate above. Volcanic processes also can be found on or near subduction zones associated with destructive plate margins. The line of volcanoes,
Outline the relationship between plate movement and volcanic activity
Outline the relationship between plate movement and volcanic activity (10 marks) Volcanic activity mainly tends to occurs on the edge of plate margins, but could potentially occur at any location, such as Hawaii where the plate boundary is underneath a hot spot, which causes the Hawaiian chain islands. It is where the magma in the mantle breaks through the lithosphere to form extrusive landforms. Shield volcanoes can be formed due to subduction and they tend to start of as a submarine volcano (under water) at either an oceanic/ oceanic convergence or a hotspot. At a hotspot, the limited magma plumes rise and go in a circular motion due to the convection currents, this eventually lead to the plumes rising up through the mantle and break through the oceanic crust. Over a long period of time, the on-going movement of the plate i.e. Pacific plate and the stationary hotspot forms an chain of many volcanoes such as the Hawaiian Chain, where Hawaii being the youngest island currently formed. At a oceanic/ oceanic convergence, the subduction of the oceanic plate tends to increase pressure in the Benioff Zone, which leads to partial melting of the plate, this is similar to composite and calderas as O-O convergence is destructive along with calderas and composite. They tend to have gentle and predictable eruptions which can cause to build up a large amount of flows, where the lava is