Natural Hazards and Tectonic Plates Quiz

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Questions and Answers

What primarily causes tectonic plates to move according to recent research?

Subduction zones

Convection currents

Magnetic field fluctuations

Slab Pull (correct)

What happens to magma as it rises in the mantle?

It loses density and evaporates

It cools down and becomes more dense (correct)

It mixes with the oceanic crust

It solidifies instantly

What is the term for the point underground where an earthquake originates?

Seismic origin

Focus (correct)

Epicentre

Magnitude point

Why do tectonic plates become stuck at their boundaries?

Due to friction between plates Signup and view all the answers

What phenomenon is caused by the sudden release of pressure when tectonic plates move?

Seismic waves Signup and view all the answers

Which characteristic of a hazard profile indicates how extensive an area an event could affect?

Magnitude Signup and view all the answers

What is the term used to describe the number of deaths caused by a hazard?

Fatalities Signup and view all the answers

Which factor contributes to the effectiveness of hazard models?

Level of development Signup and view all the answers

Which challenge is associated with using hazard profiles for decision-making?

Unpredictability of hazards Signup and view all the answers

Which aspect of a hazard indicates how much warning time there is before it occurs?

Speed of onset Signup and view all the answers

Which of the following is NOT a characteristic included in a hazard profile?

Political Influence Signup and view all the answers

What is a significant consequence of rapid urbanization regarding hazards?

Dangerous settlement locations Signup and view all the answers

Which of the following can make essential services harder to access in hazard-prone areas?

Lack of basic services Signup and view all the answers

What type of seismic wave travels only through solid rocks?

Secondary waves Signup and view all the answers

Which seismic wave is characterized by a rolling motion that produces vertical ground movement?

Rayleigh waves Signup and view all the answers

What phenomenon can occur when the soil behaves like a liquid due to an earthquake?

Soil liquefaction Signup and view all the answers

Which factor does NOT influence the intensity of seismic waves felt at a location?

Time of day Signup and view all the answers

Which seismic wave travels the fastest?

Primary waves Signup and view all the answers

What can tsunamis be caused by?

Upward displacement of water by jolt of oceanic crust Signup and view all the answers

What is the most common primary hazard leading to destruction during an earthquake?

Structural damage from vibrations Signup and view all the answers

How does the intensity of seismic waves change as they move away from the epicenter?

Intensity decreases Signup and view all the answers

What is one of the key roles of NGOs in disaster response?

Providing funds and coordination for rescue efforts Signup and view all the answers

Which factor contributes to a population's vulnerability to hazards according to the information?

High population density Signup and view all the answers

What does the Risk Poverty Nexus suggest?

Poverty is both a cause and result of natural hazards Signup and view all the answers

What type of inequality relates to housing and agricultural productivity?

Asset inequality Signup and view all the answers

How does unstable political governance affect a country’s readiness for hazards?

It can negatively impact preparedness and recovery Signup and view all the answers

What aspect of inequality involves the ability to secure access to services?

Social status inequality Signup and view all the answers

What is a consequence of high population density in terms of hazard impact?

Higher number of people affected by hazards Signup and view all the answers

What challenges do remote, rural areas face regarding disaster response?

Poor transport links that hinder rescue efforts Signup and view all the answers

What is one of the main aims when coping with a disaster?

Rescuing people Signup and view all the answers

Which of the following is NOT a short-term recovery action for a disaster?

Reopening schools Signup and view all the answers

What does the micro approach primarily emphasize in earthquake management?

Strengthening individual buildings Signup and view all the answers

Which of the following is an example of modifying vulnerability?

Installing monitoring systems for volcanoes Signup and view all the answers

What is one disadvantage of building resistant structures?

They require high-cost investment Signup and view all the answers

Which modification approach involves community preparedness?

Modify the Vulnerability Signup and view all the answers

What is a primary disadvantage of using tsunami defences?

They require high costs for construction Signup and view all the answers

In the context of volcanoes, what does monitoring help accomplish?

Predict eruptions and facilitate evacuations Signup and view all the answers

Which type of modification primarily helps in managing the loss during a disaster?

Long-term aid and reconstruction Signup and view all the answers

What is a proposed advantage of using lava diversion techniques?

They can slow down and divert lava flows Signup and view all the answers

Why might community-led recovery operations be crucial in isolated areas post-disaster?

They can operate independently of outside aid Signup and view all the answers

Which of the following is a disadvantage of community preparedness programs?

They might be harder to implement in remote areas Signup and view all the answers

What is one way to modify land use to reduce disaster vulnerability?

Establishing zoning regulations Signup and view all the answers

What factor contributes to urban areas being more adversely affected by hazards?

Presence of critical infrastructure Signup and view all the answers

How can land-use planning mitigate risks associated with hazards?

By preventing settlement in high-risk areas Signup and view all the answers

What role does preparedness play in reducing vulnerability to hazards?

It raises awareness and teaches effective responses during disasters. Signup and view all the answers

Which of the following is a characteristic of tectonic mega-disasters?

Large scale disasters affecting significant areas and populations. Signup and view all the answers

What is a secondary hazard that can increase vulnerability if basic needs are not met?

Outbreak of diseases Signup and view all the answers

How can corruption influence a community's vulnerability to hazards?

By diverting resources from essential services. Signup and view all the answers

What was a consequence of the 2011 Eyjafjallajökull eruption?

Closure of European airspace causing trade halts. Signup and view all the answers

What impact do tectonic mega-disasters have on globalized businesses?

They significantly damage operations and create economic uncertainty. Signup and view all the answers

Study Notes

Tectonic Processes and Hazards

A hazard is a potential threat to human life and property, either hydro-meteorological (caused by climate processes) or geophysical (caused by land processes).
Geophysical hazards usually occur near plate boundaries, where plates move at different speeds and directions, causing collisions, earthquakes, and volcanic activity. Intra-plate earthquakes can also occur, but the causes aren't fully understood; often pre-existing weaknesses in the crust are reactivated.
Volcanic hotspots are areas of the lithosphere (Earth's crust and upper mantle) with unusually high temperatures due to magma upwelling from the core, like the Ring of Fire.
Large earthquakes mostly occur at convergent or conservative boundaries.
Oceanic Fracture Zones (OFZs) are belts of activity through the oceans and along mid-ocean ridges.
Continental Fracture Zones (CFZs) are belts of activity along mountain ranges from Spain through the Alps to the Middle East and the Himalayas.

Tectonics Trends Since 1960

The total number of recorded hazards has increased.
The number of fatalities has decreased, but there are spikes during mega-disasters.
The total number of people affected by tectonic hazards is increasing, due to population growth.
The economic costs of hazards and disasters have increased, partly because of increased development costs for infrastructure in more developed countries, as well as rising insurance policies.
Reporting disaster impacts (e.g., fatalities) is difficult and controversial due to differing methodologies and difficulties in accessing remote or high-density areas.

Characteristics of the Earth's Structure

The Earth consists of four sections:
- Crust: Also known as the lithosphere, the uppermost layer, thinnest and least dense; oceanic crust is 7km, while continental crust can be up to 70km thick.
- Mantle: May include asthenosphere, largely composed of silicate rocks, rich in iron and magnesium. Convection currents in the mantle are caused by a temperature gradient toward the core.
- Outer Core: Dense, semi-molten rocks featuring iron and nickel alloys. At a depth of 2,890 km to 5,150 km below the Earth's surface
- Inner core: Similar composition to the outer core, but solid due to extreme pressure. The core's high temperature is due to primordial heat and radiogenic heat.
Heat created in the inner core radiates and is conducted through the mantle into the asthenosphere.

Different Plate Boundaries

At plate boundaries, plates move towards each other (destructive), away from each other (constructive), or parallel to each other (conservative).
Different landforms are created due to these interactions.
- Constructive: Rift valleys, ocean ridges, volcanoes, and fold mountains.
- Destructive: Ocean trenches, island arcs, volcanoes, and fold mountains.
- Conservative: Earthquakes and fault lines.

Plate Boundaries - Further Details

Continental and Oceanic: Denser oceanic plate subducts beneath continental plate creating an ocean trench. The melted oceanic crust, formed through this process, creates pressure building up and erupting as composite volcanoes. Sediment pushed upwards during subduction forms fold mountains.
Oceanic and Oceanic: Heavier plate subducts creating an ocean trench, and fold mountains as well. Pressure causes underwater volcanoes which burst through the oceanic plate creating new land (island arcs).
Continental and Continental: Neither plate is dense enough to subduct. Instead, they pile up to create fold mountains.

Earthquakes

Plates do not move smoothly, instead they get stuck due to friction. Pressure builds until the plates eventually give way, releasing the energy in seismic waves.
The focus (hypocenter) is the underground point of origin, while the epicenter is the surface point directly above it.
Seismic waves (Primary, Secondary, Love, Rayleigh) travel through the earth at different speeds and have varying degrees of destruction, with the Secondary and Love waves being the most destructive as they have large amplitudes.
Secondary hazards of earthquakes include soil liquefaction (shaking causes water to separate the soil particles creating a liquid effect), landslides (shakings weaken rock faces and may cause material to move), and tsunamis.

Tsunamis

Tsunamis are generated in subduction zones when an oceanic crust shifts during a quake.. The water above the shifted crust is displaced, causing a wave that travels at great speed. As this water approaches the coast, friction occurs between the seabed and the wave, causing the wave height to increase dramatically.
They have several characteristics—speed, wave amplitude, and duration—and their impact depends on population density, coastal defenses, and warning systems.

Volcanoes

Primary hazards include lava flows (streams of molten rock travelling fast), pyroclastic flows (a mixture of hot rocks, lava, ash, and gases), and tephra and ash flows (explosive volcanic rocks and ash).
Secondary hazards include volcanic gases, lahars, and mudflows.

Tectonic Hazard Profiles

A hazard profile helps compare physical characteristics of hazards and aid decision-making in resource allocation. Key characteristics include frequency (how often it occurs), magnitude (impact area), duration, speed of onset (warning time), fatalities, economic loss, and spatial predictability (predictability of impact area).

Disaster Classification and Theories

A disaster is a serious disruption to a community or society where the damage exceeds its ability to cope using its own resources.
Risk = (Hazard x Vulnerability) / Capacity to cope.
Hazard, vulnerability, and capacity (to cope) impact the risk profile of a community.
Degg’s Model describes hazards as events that will only occur when a vulnerable population is exposed. Different organizations and individuals may use different definitions of hazard, depending on their interests

The Pressure and Release Model (PAR)

The PAR model analyzes factors that make a community or population vulnerable to a hazard. It proposes that natural hazards exist on one side; factors that increase vulnerability are on the other.
Root causes (e.g., political or economic instability within a country); dynamic pressures or unsafe conditions can potentially contribute to vulnerability.

Measuring Tectonic Events

Volcanic Explosivity Index (VEI): Measures the relative explosiveness of a volcanic eruption, based on ejected material and duration.
Modified Mercalli Intensity Scale: A subjective scale measuring an earthquake's destructiveness, focused on observed impacts.
Moment Magnitude Scale (MMS): Measures the amount of energy released during an earthquake. The Richter Scale measures the amplitude of seismic waves, often compared to other methods.

Managing Tectonic Hazards

Responding to and managing hazards involves prevention, preparedness, mitigation, and adaptation.

Tectonic Mega-Disasters

Large-scale disasters that affect extensive geographic areas or large populations.
Require significant international support and aid.

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Description

Test your knowledge on the dynamics of tectonic plates and their impact on natural hazards. This quiz covers key concepts such as the causes of plate movement, earthquake origins, and the effectiveness of hazard models. Perfect for students studying geology and environmental science.