Edexcel Specification focus:
‘Hazard profiles of earthquake, volcano and tsunami events to show severity of social and economic impact in developed, emerging and developing countries.’
This topic compares different tectonic hazards using profiles that reveal how severity and impact vary with development levels and physical characteristics.
Understanding Hazard Profiles
Hazard profiles are tools used to compare the physical characteristics and potential impacts of different types of tectonic hazards, such as earthquakes, volcanic eruptions, and tsunamis. They provide a visual or tabulated representation of a hazard’s features and allow geographers to assess the severity and likely impacts on societies.
Hazard Profile: A diagram or table that compares the key characteristics of different hazards to assess their potential risk and impacts.
These profiles consider various attributes that influence the extent of a hazard’s disruption and help evaluate how hazard characteristics affect social and economic impacts in different contexts.
Key Characteristics of Hazard Profiles
Hazard profiles typically examine the following features:
Magnitude – The amount of energy released by a tectonic event. Measured using scales such as the Moment Magnitude Scale (MMS) for earthquakes and the Volcanic Explosivity Index (VEI) for volcanic eruptions.
Speed of Onset – The time between the origin of the hazard and its first effects.
Duration – How long the hazard event lasts.
Areal Extent – The spatial area affected by the hazard.
Frequency – How often the hazard occurs in a given location or globally.
Spatial Predictability – How accurately the location of the hazard can be forecast.
These variables help create a comparative profile of hazards to determine which pose the greatest risk in specific geographic or development contexts.
Comparing Tectonic Hazards Using Hazard Profiles
Earthquakes
Magnitude: Can range from minor to devastating (e.g., MMS 2.0 to 9.0+).
Speed of Onset: Sudden, with little or no warning.
Duration: Typically brief (seconds to minutes), though aftershocks may last days or weeks.
Areal Extent: Varies depending on depth and crustal structure.
Frequency: High in tectonically active regions.
Spatial Predictability: Low – difficult to predict precise location and timing.
Earthquakes often cause severe social impacts (casualties, displacement) and economic damage (infrastructure loss, business interruption), particularly in densely populated or poorly prepared areas.
Volcanic Eruptions
Magnitude: Measured on the VEI (0–8); depends on gas content, magma viscosity, and eruption style.
Speed of Onset: Variable; sometimes preceded by warning signs such as tremors and gas emissions.
Duration: Can last from hours to months.
Areal Extent: Usually localised, though ash clouds can spread globally.
Frequency: Varies significantly between volcanoes.
Spatial Predictability: Moderate – location often known, but eruption timing is harder to forecast.
Volcanoes can produce long-term disruption through ash falls, lahars, and gas emissions, especially in regions with high exposure and limited resilience.
Tsunamis
Magnitude: Indirectly related to the magnitude of the triggering earthquake; waves can reach heights of over 30 metres.
Speed of Onset: Very rapid once triggered; coastal areas may have minutes to a few hours of warning.
Duration: Single or multiple waves over hours.
Areal Extent: Extensive, affecting entire coastlines and sometimes across ocean basins.
Frequency: Less frequent than other tectonic hazards.
Spatial Predictability: Low – only predictable once a triggering earthquake occurs.
Tsunamis can cause catastrophic human and economic losses, particularly in low-lying coastal areas without early warning systems.
Impact Severity Across Levels of Development
The severity of a tectonic hazard is not determined solely by the physical characteristics. Human factors, particularly development level, influence outcomes significantly.
Developed Countries
Typically have strong infrastructure, building regulations, and early warning systems.
Lower death tolls but high economic losses due to valuable assets.
Faster response and recovery, with access to insurance and aid.
Emerging Countries
Growing urbanisation may increase exposure, but improved governance may support resilience.
Mixed impacts: potentially high casualties and economic disruption.
Response and recovery may be uneven.
Developing Countries
High vulnerability due to poverty, inadequate infrastructure, and limited access to healthcare.
Often suffer the greatest social impacts – higher death tolls, displacement, and long-term poverty increases.
Weak emergency response capacity and slow recovery.
Vulnerability: The degree to which a population is susceptible to harm from hazard events due to physical, social, economic, or environmental factors.
For example, a magnitude 7.0 earthquake may cause far greater devastation in a poorly governed, densely populated developing nation than a higher magnitude event in a developed one with strict building codes.
Using Hazard Profiles to Assess Risk and Prepare
Hazard profiles serve as essential tools for:
Risk assessment: Identifying which hazards are most dangerous in particular locations.
Disaster preparedness: Informing planning, zoning, and early warning systems.
Policy-making: Supporting investment in mitigation strategies in vulnerable regions.
By systematically comparing hazard characteristics, decision-makers can prioritise actions to reduce social vulnerability and limit economic damage, improving resilience across development levels.
FAQ
Primary hazards like ground shaking or lava flows are usually included directly in hazard profiles because they result from the main tectonic process. They are measured using attributes such as magnitude, speed of onset, and duration.
Secondary hazards such as tsunamis, lahars, or landslides may require separate profiles or be included with caution, as they often have different onset speeds, durations, and areal extents. Including secondary hazards can complicate comparisons but gives a fuller understanding of overall risk.
Spatial predictability refers to how accurately the location of a hazard can be forecast. This is critical for planning and risk reduction.
High spatial predictability (e.g. volcanoes) allows authorities to implement zoning laws and prepare evacuations.
Low predictability (e.g. earthquakes on transform boundaries) increases vulnerability because communities cannot easily relocate or protect assets.
Understanding predictability helps assess the practical challenges in hazard management strategies.
Yes, hazard profiles are not limited to comparing different types of hazards; they are also useful for comparing events of the same type in different contexts.
For example, two earthquakes of similar magnitude can have:
Different speeds of onset (depending on precursor activity),
Different durations (influenced by rupture length),
Vastly different impacts due to local infrastructure and governance.
This allows geographers to isolate the effect of human and geographical variables on hazard severity.
Data for hazard profiles is drawn from a combination of scientific instruments and post-event analysis.
Sources include:
Seismographs and GPS to measure magnitude and duration,
Satellite imagery to assess areal extent,
Historical records for frequency,
Observational data and local reports for speed of onset and predictability.
Profiles may be refined over time as more accurate data becomes available or as analysis methods improve.
Interpretation depends on a country's development level, risk tolerance, and governance structure.
A developed country might view a high-magnitude hazard as manageable if it has mitigation infrastructure.
A developing country may consider the same hazard highly dangerous due to inadequate emergency services or poor building standards.
Thus, the same profile can lead to very different priorities in planning, response, and funding allocation.
Practice Questions
Question 1 (2 marks):
Define what is meant by a hazard profile and explain one of its uses in comparing tectonic hazards.
Question 1 (2 marks)
1 mark for a correct definition of hazard profile:
E.g., A hazard profile is a diagram or table that compares the physical characteristics of different hazards to assess their potential risk and impacts.
1 mark for a valid use in comparison:
E.g., They allow geographers to compare characteristics like magnitude, duration or predictability to identify which hazards pose greater risks.
Question 2 (6 marks):
Explain how hazard profiles help assess the severity of tectonic hazards in countries at different levels of development.
Question 2 (6 marks)
Award 1 mark for each valid point or developed explanation. Maximum 3 marks may be awarded for description alone. Credit use of appropriate terminology (e.g. magnitude, spatial predictability, vulnerability).
1 mark: Hazard profiles show features like magnitude, speed of onset, and areal extent.
1 mark: These features influence how severe the impact is likely to be.
1 mark: In developing countries, high vulnerability and poor infrastructure may worsen the impact, even if the hazard has moderate characteristics.
1 mark: Developed countries may have higher magnitude events but suffer lower social impacts due to preparedness and governance.
1 mark: Hazard profiles help prioritise resource allocation and preparedness strategies.
1 mark: The same type of hazard (e.g. tsunami) may have different effects depending on governance, healthcare, and early warning systems.
Max 6 marks. Use a point-development structure for clarity and ensure answers are framed within the context of hazard profiles.
