1.2.3
Comparing Hazards
Measuring the Intensity of Tectonic Hazards
Measuring the Intensity of Tectonic Hazards
The magnitude and intensity of tectonic hazards are measured using a variety of different scales.
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Earthquake magnitude
Earthquake magnitude
- The amount of energy released is measured by the Moment Magnitude Scale (MMS), which is a version of the old Richter scale.
- The MMS goes from 1 to 10, with a higher number meaning greater magnitude.
- The scale is also logarithmic. This means that an increase of 1 unit of magnitude increases the amount of shaking by 10, but the amount of energy released by 30.
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Earthquake damage
Earthquake damage
- The damaging effects of earthquakes are measured by the Mercalli scale.
- The Mercalli scale measures the intensity of shaking on a scale of 1 to 12 (usually given as Roman numerals).
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Volcano magnitude
Volcano magnitude
- Volcano magnitude is measured by the Volcanic Explosivity Index (VEI).
- The VEI is based on the volume, duration and column height of eruptions.
- The explosivity is related to the type of magma and the type of plate boundary that the volcano is located on.
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VEI examples
VEI examples
- Effusive eruptions of basaltic lavas with low VEI (0 to 3) normally happen on constructive boundaries.
- Explosive eruptions with high VEI (4 to 7) happen on destructive boundaries.
Hazard Profiles
Hazard Profiles
Hazard profiles can be used to compare the characteristics of tectonic hazards.
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What do hazard profiles show?
What do hazard profiles show?
- Hazard profiles summarise the physical processes shared by all hazards so that decision-makers can determine which areas are most at risk.
- Hazard profiles show how different types of hazards vary in:
- Magnitude.
- Speed of onset.
- Areal extent (the area that will be affected).
- Duration.
- Frequency.
- Spatial predictability.
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High-risk events
High-risk events
- Events which present the highest risk have:
- High magnitudes.
- Low frequencies.
- Rapid speeds of onset.
- Low spatial predictability.
- Large areal extents.
- These high-risk events happen mostly at subduction and collision zones.
2005 Kashmir Earthquake
2005 Kashmir Earthquake
Kashmir, in Northern India, was hit by a severe earthquake in 2005, killing at least 79,000 people.
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Hazard profile
Hazard profile
- A high magnitude (MMS 7.6) earthquake hit Kashmir in 2005, with a ground-shaking intensity of VII (severe).
- The speed of onset was very rapid, so there was a limited chance of evacuating to a safe area.
- Damage was centred on Muzaffarabad but spread over a large area of more than 1000 km2
- Ground shaking lasted 30–45 seconds (a short duration), but landslides triggered by the earthquake continued for some time, as did aftershocks up to magnitude MMS 6.4.
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Hazard profile cont.
Hazard profile cont.
- Earthquakes don't hit Kashmir often. The previous major earthquake in Kashmir was in 1905, so there was no ‘collective memory’ of the risks and impacts of earthquakes in the region.
- Spatial predictability was low. Kashmir is in a ‘seismic gap’, i.e. an area of known risk that had not experienced an earthquake for some time.
1Tectonic Processes & Hazards
1.1Tectonic Processes & Hazards
1.2Natural Disasters
1.3Natural Disaster Case Studies
1.4Trends & Patterns
2Option 2A: Glaciated Landscapes & Change
2.1Glaciated Landscapes Over Time
2.2Periglacial Landscapes
2.3Glacial Processes
2.4Glacial Landforms
3Option 2B: Coastal Landscapes & Change
3.1Coastal Landscapes
3.2Coastal Erosion & Deposition
3.3Coastal Risks
4Globalisation
4.1Globalisation
4.2Negatives of Globalisation
4.3Global Shift
4.5Culture
4.6Measuring Development
5Option 4A: Regenerating Places
5.1Types of Economies
5.2Function of Places
5.3Regeneration
5.4Regeneration Case Studies
6Option 4B: Diverse Places
6.1Population Structure
6.2Past & Present Connections
6.3Urban & Rural Spaces
6.4Diversity
6.5Urban & Rural Case Studies
6.6Case Study - Tower Hamlets
6.7Case Study - Sturton-le-Steeple
7The Water Cycle & Water Insecurity (A2 only)
7.1Hydrological Processes Global to Local
7.2Influences on the Water Cycle
7.3Water Insecurity
8The Carbon Cycle & Energy Security (A2 only)
8.1The Carbon Cycle
8.2Energy Consumption
8.3Alternative Energy
8.4Growing Demand for Resources
9Superpowers (A2 only)
9.1Superpowers
9.2Hard & Soft Power
9.2.1Hard & Soft Power
9.2.2Emerging Powers - China Rivalry
9.2.3Emerging Powers - Chinese Sources of Power
9.2.4Emerging Powers - Brazil
9.2.5Emerging Powers - Russia
9.2.6Emerging Powers - India
9.2.7Theories of Development
9.2.8Power Case Studies: Chinese One Belt One Road
9.2.9Power Case Studies: Pakistan Nuclear Arms
9.2.10Power Case Studies: OPEC
9.3IGOs, TNCs & Alliances
10Option 8A: Health & Human Rights (A2 only)
10.1Human Development
10.2Role of Governments & IGOs
10.3Human Rights
10.4Interventions
11Option 8B: Migration & Identity (A2 only)
11.1Globalisation & Migration
11.2Consequences of Migration
11.3Nation States
11.4Responses to Global Migration
Jump to other topics
1Tectonic Processes & Hazards
1.1Tectonic Processes & Hazards
1.2Natural Disasters
1.3Natural Disaster Case Studies
1.4Trends & Patterns
2Option 2A: Glaciated Landscapes & Change
2.1Glaciated Landscapes Over Time
2.2Periglacial Landscapes
2.3Glacial Processes
2.4Glacial Landforms
3Option 2B: Coastal Landscapes & Change
3.1Coastal Landscapes
3.2Coastal Erosion & Deposition
3.3Coastal Risks
4Globalisation
4.1Globalisation
4.2Negatives of Globalisation
4.3Global Shift
4.5Culture
4.6Measuring Development
5Option 4A: Regenerating Places
5.1Types of Economies
5.2Function of Places
5.3Regeneration
5.4Regeneration Case Studies
6Option 4B: Diverse Places
6.1Population Structure
6.2Past & Present Connections
6.3Urban & Rural Spaces
6.4Diversity
6.5Urban & Rural Case Studies
6.6Case Study - Tower Hamlets
6.7Case Study - Sturton-le-Steeple
7The Water Cycle & Water Insecurity (A2 only)
7.1Hydrological Processes Global to Local
7.2Influences on the Water Cycle
7.3Water Insecurity
8The Carbon Cycle & Energy Security (A2 only)
8.1The Carbon Cycle
8.2Energy Consumption
8.3Alternative Energy
8.4Growing Demand for Resources
9Superpowers (A2 only)
9.1Superpowers
9.2Hard & Soft Power
9.2.1Hard & Soft Power
9.2.2Emerging Powers - China Rivalry
9.2.3Emerging Powers - Chinese Sources of Power
9.2.4Emerging Powers - Brazil
9.2.5Emerging Powers - Russia
9.2.6Emerging Powers - India
9.2.7Theories of Development
9.2.8Power Case Studies: Chinese One Belt One Road
9.2.9Power Case Studies: Pakistan Nuclear Arms
9.2.10Power Case Studies: OPEC
9.3IGOs, TNCs & Alliances
10Option 8A: Health & Human Rights (A2 only)
10.1Human Development
10.2Role of Governments & IGOs
10.3Human Rights
10.4Interventions
11Option 8B: Migration & Identity (A2 only)
11.1Globalisation & Migration
11.2Consequences of Migration
11.3Nation States
11.4Responses to Global Migration
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