Mt St Helens Volcanic Eruption Case Study - Mount St Helens, Rocky Mountain Fold, North America.

Mt St Helens Volcanic Eruption Case Study Where: Mount St Helens, Rocky Mountain Fold, North America. What Happened: On the 18th May 1980 at 0833 hours, Mt St Helens erupted. Seismologists studied beforehand and started to recognise that an eruption would occur soon. It first started when 100+ earthquakes were recorded from the 15th to the 21st of March. The earthquake that occurred on the 20th March 1980 gave scientists the early warnings of its first eruption since 1857. Although there were earthquakes recorded from the 15th, the tremor measuring 4.1 on the Richter scale on the 20th gave the signs of preparation for volcanic activity. What Happened (Continued): From the start of early May, Scientists started to notice something very unusual. A bulge started to appear on the North side and it was increasing in size by about 1.5m a day. Scientists were really worried now. The eruption wouldn't take place from the crater but from this bulge. Pressure was rising and the bulge was growing. The danger zone they had marked out would be wrong and people in other locations were in danger. On the 18th May, 0830 hours, Ash and steam erupted. Two minutes later, an earthquake shook the mountain. This earthquake measured 5 on the Richter scale and also gave the bulge a move forwards and downwards. 1000's of tonnes of rocks, glaciers, ice, soil and mud raced downhill within a minute.

  • Word count: 686
  • Level: AS and A Level
  • Subject: Geography
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It is logical to think that the hazards impact depends on a countries level of development. For example, a hazard in a MEDC might cause huge amounts of damage because of the costs of buildings there

Discuss the view that the impact of hazards depends on a countries level of development. It is logical to think that the hazards impact depends on a countries level of development. For example, a hazard in a MEDC might cause huge amounts of damage because of the costs of buildings there and the amount of people located in one small area. On the other hand in a LEDC the hazard may cause more damage because the people are less developed and the buildings are less adapted to resist a hazard. When thinking about earthquakes we have to take into consideration the infrastructure of the MEDC and LEDC in question. Certain MEDCs that experience frequent earthquakes try to make their buildings 'earthquake-proof'. Examples include Japan, and San-Francisco in America. The Oct. 17, 1989 Loma Prieta earthquake occurred in the least-populated area of the generally urban San Francisco peninsula. Construction standards in the area are relatively high, and the populace relatively prepared. However, soft, highly-saturated soils near San Francisco Bay caused some spectacular failures of large highway structures unusually far away from the event. Even though it was rush hour, many fewer cars were on the roads due to the start of the opening game of the World Series, being played locally. Thus deaths were limited to about 75. In 1995 the Kobe earthquake was one of the most devastating earthquakes

  • Word count: 699
  • Level: AS and A Level
  • Subject: Geography
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An earthquake struck on the 17th January at 5:46 am in the south-central part of Japan.

An earthquake struck on the 17th January at 5:46 am in the south-central part of Japan. This earthquake was 7.2 on the Richter scale and caused mass destruction. It was called The Great Hanshin Earthquake. Its focus was only 30 km below ground. Shock waves travelled to the surface and splintered buildings, roads and mains supplies of gas water and electricity. The Japanese were in a hard to live state. This also hit Osaka and Kyoto. Kobe has a 1.5 million population its self. All children experiencing the vibrating dived under their desks using them as shelters for protection. This stopped falling things hitting them. The plates which came into contact with each other were the Pacific and Eurasian plates. The strong ground shaking lasted for over 20 seconds. Hundreds of aftershocks remained for days after the incident, which worried people. Evacuation shelters opened a couple of days later on the 24th January. They slowly began to realise there wasn't enough so they used schools to store people. On the 26th January 566 shelters had been opened. Some had to live in tents, BUT at night it dropped below freezing point! Kobe finally managed to get their Electricity restored on January 23rd, Water service on the 31st March and Gas 11 days later in April. Schools were quick to open their doors. They opened 1 month later. The damage caused, spread over a 100km radius

  • Word count: 778
  • Level: AS and A Level
  • Subject: Geography
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Evaluating climate change

CLIMATE CHANGE A critical analysis Climate change is a complex subject, with genuine areas of uncertainty and scientific controversy. There are also a number of misunderstandings which are recycled, often by non-climate scientists, and portrayed as scientific fact. Over hundreds, thousands and millions of years 'natural climatic changes have taken place. There appear to have been large- scale cycles of climatic variation. It would appear that climate change therefore is not a recent phenomenon as it has occurred in past cycles. Climate change is happening and humans are contributing to it. Temperatures provide the clearest evidence that the climate is changing and globally the average temperature has risen by more than 0.7 °C over the last 100 years. The natural greenhouse gas effect keeps Earth much warmer than it would otherwise be, without it Earth would be extremely cold. Greenhouse gases such as carbon dioxide, methane and water vapour behave like a blanket around Earth. These gases allow the Sun's rays to reach Earth's surface but impede the heat they create from escaping back into space. Any increases in the levels of greenhouse gases in the atmosphere mean that more heat is trapped and global temperatures increase - an effect known as 'global warming'. There is indisputable evidence from observations that the Earth is warming. Concentrations of CO2, created

  • Word count: 1236
  • Level: AS and A Level
  • Subject: Geography
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Can Human Innovation Greatly Minimise The Impact Of Earthquakes?

Robert Hicks Can Human Innovation Greatly Minimise The Impact Of Earthquakes? Looking at the effects of an earthquake is truly amazing; the destruction caused can be catastrophic! They can leave a trail of untold damage including, hospitals being disabled, fractured highways, damaged airports, damaged harbours, free flowing sewerage, water contamination, flaming gas lines, oil spilling into the sea, landslides, floods, collapsed buildings and the obvious violent shaking of the earth or ground. This short essay will be looking at the effects of an earthquake, whether human innovation has a role to play and seeing where or why there's a need for it? California and particularly San Francisco have been prone to some of the most prominent earthquakes known; this is due to the location of the continent and state. San Francisco is sited on the San Andreas Fault, the edge of the North American plate (that carries most of the continent) and the edge of the Pacific plate (which carries most of the California coastline). Where these two plates meet there is a hive of activity as they attempt to move past each other at an average speed of four centimetres(cm) per year (a similar rate to which finger nails grow). This action normally causes small tremors, but sometimes the rocks can't stand the enormous stress put on them by this process. As they force their way past each other an

  • Word count: 1161
  • Level: AS and A Level
  • Subject: Geography
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Te Wairo Buried!

the 1860s, then repopulated a few years later as the staging post for travellers to the Pink and White Terraces. The eruption of Mount Tarawera was the most recent of numerous volcanic events in the Rotorua region over the last 20,000 years. It destroyed the Terraces and buried Te Wairoa and two smaller villages under hot, heavy ash and mud. More than 150 lives were lost. A meandering pathway, set among trees and meadows beside the Te Wairoa Stream, connects the Buried Village's excavated dwellings. A museum introduces visitors to the fascinating drama and brings history alive today. Violent and unexpected, the eruption of the Tarawera volcano during the early hours of June 10, 1886, was New Zealand's greatest natural disaster. At 1.40 am, the supposedly extinct volcano, Mount Tarawera exploded. The three domes on this now flat-topped volcano blew and demolished one side of the mountain. Over the next six hours several eruptions occurred and a 17 kilometre wound of craters and deep, elongated pits was created. The eruption ripped away the bed of the nearby Lake Rotomahana burying Te Wairoa and other nearby villages with mud, rock and ash. The explosion deposited ash and debris over an area of 16 000 km2 and the town of Rotorua was evacuated. The famed Pink and White Terraces, a giant fanlike silica formation which glittered in pink, white and turquoise as water ran down

  • Word count: 1231
  • Level: AS and A Level
  • Subject: Geography
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Why Are Natural Hazards Rarely Completely Natural?

Why Are Natural Hazards Rarely Completely Natural? Throughout the world, natural hazards are a frequent occurrence. They come in the forms of hurricanes, earthquakes, volcanic eruptions, and floods, to name but a few. On a range of scales they create disaster, destruction, loss of life and of livelihood. Natural processes have occurred in the natural environment for millions of years. They are events that happen naturally, e.g. blizzards and floods. A natural process only becomes a natural hazard when the risk of human loss is presented. To put it in context, a flood in an unoccupied valley is a natural process, whereas a flood in a valley where a village is situated is a natural hazard. Natural disasters take natural hazards to the next level. A natural disaster is when a natural hazard results in extensive loss of life or property. Natural disasters cannot happen where there are no humans, as a natural disaster in a baron desert would simply remain a natural process. Therefore a natural hazard requires human presence simply to exist, meaning that it would not be a completely natural process. Let us take the case of the flooding of Boscastle, Cornwall, in early August of 2004. Boscastle is situated in the channel of a steep valley, very close to the convergence of two local rivers. An unusually long period of heavy rain was inflicted upon the valley, due to the lack of

  • Word count: 1273
  • Level: AS and A Level
  • Subject: Geography
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With aid of diagrams, describe and explain the processes and landforms operating and landforms associated with tectonic activity.

. With aid of diagrams, describe and explain the processes and landforms operating and landforms associated with tectonic activity. Scientists now have a fairly good understanding of how the plates move and how such movements relate to earthquake activity. Most movement occurs along narrow zones between plates where the results of plate-tectonic forces are most evident. There are three types of plate boundaries: * Divergent boundaries -- where new crust is generated as the plates pull away from each other. * Convergent boundaries -- where crust is destroyed as one plate dives under another. * Transform boundaries -- where crust is neither produced nor destroyed as the plates slide horizontally past each other. Divergent boundaries Divergent boundaries occur along spreading centres where plates are moving apart and new crust is created by magma pushing up from the mantle. Picture two giant conveyor belts, facing each other but slowly moving in opposite directions as they transport newly formed oceanic crust away from the ridge crest. Perhaps the best known of the divergent boundaries is the Mid-Atlantic Ridge. This submerged mountain range, which extends from the Arctic Ocean to beyond the southern tip of Africa, is but one segment of the global mid-ocean ridge system that encircles the Earth. The rate of spreading along the Mid-Atlantic Ridge averages about 2.5

  • Word count: 1583
  • Level: AS and A Level
  • Subject: Geography
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Explain why some physical environments attract more human activity than others

Geography essay Explain why some physical environments attract more human activity than others. (25 marks) Human activity can be defined as the actions of people, and can be categorised into settlement, agriculture, industry, communication and tourism. Human activity can be dependant on the development of a location, and this can be directly linked to the physical environment. Each physical environment can provide opportunities and risks to humans and human activity, and dictates the level and type of activity present. To explain why this is, I intend to discuss three different physical environments, including tectonics, coastal and fluvial; the way in which they affect human activity in all categories. Tectonic locations have a large influence over in which human activity is situated. One main feature of tectonics is volcanic activity. Volcanoes occur in various areas all over the world, but the nature of the volcanic activity dictates the way it can be utilised or to the extent to which it is a hazard. If the volcano is on a small scale, hardly if ever erupting then it is likely there will be a lot of human activity present. Most human activity around volcanoes drops into the agricultural category. The fertile soils are very useful, mainly in LEDCs were agriculture is the main way of life. This provides the most important source of income in less developed countries

  • Word count: 1595
  • Level: AS and A Level
  • Subject: Geography
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Assess the extent to which people may be regarded as the creators of hazards

Assess the extent to which people may be regarded as the creators of hazards "Those elements in physical environment harmful to man and caused by forces extraneous to him". Definition of natural hazards, by I. Burton and R.W. Kates (1964). A hazard only becomes a hazard if it affects, or threatens to affect people. It is essentially man centered. If no people are at risk, it is not a hazard. (See fig 1.0) The more people living in hazardous environments, and the higher the level of development, the more damage caused by hazards. "Venerability to any kind of hazard is essentially determined by poverty". Maskney (1989). Fig 1.0 Natural hazards happen because the Earth is always moving, and the tectonic plates are constantly grinding next door to each other. Where the plate boundaries lie, most natural hazards occur, such as Earthquakes and Volcanic eruptions. Death rates from natural hazards and disasters seems to be increasing. This is due to population growth, economic growth and the increasing use of hazardous environments. In the 1970's and 1980's about three million people were killed by natural hazards and they affected a further 820 million people. They have also cost the global economy an estimated US $40 billion in losses and US $15 billion in relief and rehabilitation. Natural hazards claim more lives in poorer countries with over 90% of deaths occurring

  • Word count: 1466
  • Level: AS and A Level
  • Subject: Geography
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