Geography A Level Edexcel
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1-1-risk-of-tectonic-hazards3 主题
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1-2-tectonic-hazards-and-impacts3 主题
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1-3-management-of-tectonic-hazards4 主题
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2-1-climate-change-and-glaciated-landscapes4 主题
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2-2-glacial-processes3 主题
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2-3-glacial-landforms-and-landscapes3 主题
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2-4-management-of-glaciated-landscapes4 主题
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3-1-coastal-processes3 主题
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3-2-coastal-landforms-and-landscapes3 主题
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3-3-coastal-erosion-and-sea-level-change3 主题
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3-4-coastal-management4 主题
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4-1-causes-of-globalisation3 主题
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4-2-impacts-of-globalisation3 主题
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4-3-consequences-of-globalisation3 主题
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5-1-place-variation3 主题
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5-2-regeneration3 主题
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5-3-management-of-regeneration3 主题
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5-4-success-of-regeneration3 主题
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6-1-population-structure-variation3 主题
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6-2-diverse-living-spaces3 主题
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6-3-demographic-and-cultural-tensions3 主题
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6-4-management-and-stakeholders3 主题
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7-1-hydrological-cycle3 主题
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7-2-factors-influencing-the-hydrological-system3 主题
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7-3-water-insecurity3 主题
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8-1-carbon-cycle3 主题
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8-2-increasing-energy-demand3 主题
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8-3-global-climate-system-links-to-carbon-and-water-cycles3 主题
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9-1-superpowers3 主题
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9-2-impacts-of-superpowers3 主题
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9-3-superpowers-and-spheres-of-influence3 主题
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10-1-human-development3 主题
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10-2-human-rights3 主题
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10-3-human-rights-and-intervention3 主题
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10-4-interventions-and-outcomes3 主题
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11-1-globalisation-and-migration3 主题
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11-2-nation-states3 主题
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11-3-managing-global-issues-and-conflicts3 主题
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11-4-threats-to-national-sovereignty3 主题
1-2-2-tectonic-hazard-profiles
Exam code:9GE0
Tectonic Hazard Magnitude
Earthquake magnitude
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Magnitude is the most common way to measure an earthquake
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It measures the energy released at the source (focus)
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The magnitude can be measured on different scales but the one which is reported on the news when a earthquake occurs is the Moment Magnitude Scale (MMS)
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It is measured using seismographs
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The MMS goes from 1 which are not felt by humans to 10
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The MMS is a logarithmic scale which means that a 6 on the scale is a ten times increase in amplitude from a 5
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The energy release is 32 times greater
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Earthquake intensity
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The intensity of an earthquake is its impact on people, as well as the built and natural environments
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The Modified Mercalli Intensity Scale is used to measure the intensity
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The scale goes from I to XII
Examiner Tips and Tricks
Remember not to confuse magnitude and intensity.
Magnitude is the amount of energy released. Whereas intensity is severity of ground shaking at a particular place based on the effects on humans, buildings and the environment.
Measuring volcanic eruptions
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Every eruption is unique some are gentle, others are hugely explosive
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The Volcanic Explosivity Index (VEI) is used to measure the size of an eruption
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This can not be measured on a scientific instrument so is calculated based on a series of measurements and observations
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These include:
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Height of material ejected into the atmosphere
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Volume of material
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Duration of the eruption
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This is a logarithmic scale from 0-8
Examiner Tips and Tricks
Magnitude is one of the key factors in the impact a hazard event has. However, it is important to remember that it is not the only factor – a magnitude 6.1 earthquake can have severe impacts in one area but the same magnitude in another area may have few impacts
Tectonic Hazard Characteristics
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Hazard profiles can be used to compare tectonic hazard events
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Hazard profiles usually include information about:
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Magnitude
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Speed of onset
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Areal extent
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Duration
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Frequency
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Spatial predictability
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Advantages
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Hazard profiles can be used to compare:
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Different hazards
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Same hazards with different processes – a volcano on a destructive boundary compared to one on a constructive boundary
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Same hazards with different human vulnerabilities – an earthquake in a developed country compared to one in a developing country
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They can also be used to plan for future events
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They are useful when looking at one hazard such as an earthquake
Disadvantages
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Hazard profiles do have disadvantages:
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Other factors may have a greater influence on the impact
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They focus on physical factors when human factors may be the most important
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Multi-hazard events are not easily represented on a hazard profile
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They are subjective
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Examiner Tips and Tricks
It is important to understand the advantages and disadvantages of using hazard profiles to compare hazards. You should be able to outline the advantages and disadvantages using real life examples.
For example, you can compare magnitude of earthquakes on a hazard profile but the correlation between magnitude and impacts is not always straightforward due to other factors such as level of development. This can be seen in the comparison of Nepal (2015) and New Zealand (2016). They both experienced 7.8 magnitude earthquakes. However the number of deaths in Nepal was almost 9,000 whereas in New Zealand it was 2. Other factors such as population density had more impact on the number of deaths.
Tectonic Hazard Profiles
Earthquakes
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Example |
Profile Features |
Social impacts |
Economic impacts |
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Haiti (Developing) – 7.0 magnitude |
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Sulawesi, Indonesia (Emerging) – 7.5 magnitude |
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Amatrice, Italy (Developed) 6.2 magnitude |
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