Tectonic Hazards

What Tectonic Hazards covers

Tectonic Hazards is examined in Component 3 Section A, compulsory. It covers earth's internal structure and plate movement, divergent plate margins, convergent margins, subduction and collision, conservative margins and hot spots, global distribution of tectonic hazards, the hazard profile and magnitude scales, types of volcano and styles of eruption, primary volcanic hazards, secondary volcanic hazards, impacts of volcanic activity at local, regional and global scales, contrasting volcanic eruptions, earthquake characteristics and seismic waves, ground shaking, liquefaction and landslides, tsunami generation and impacts, impacts of earthquakes in contrasting contexts, human factors affecting risk and vulnerability, monitoring, prediction and warning and mitigation and the hazard management cycle.

The 18 subtopics

Each one has its own page.

• Earth's internal structure and plate movementDepth of the Gutenberg discontinuity and what it separates, two main sources of the Earth's internal heat and how mantle convection currents move tectonic plates.Open →
• Divergent plate marginsOcean ridge formed by the divergent margin in the Atlantic, typical spreading rate for the Mid-Atlantic Ridge and transform faults.Open →
• Convergent margins, subduction and collisionThree types of convergent plate margin, plates and the features of the Andean margin and benioff zone.Open →
• Conservative margins and hot spotsSan Andreas Fault, conservative margin outside the United States and elastic rebound theory.Open →
• Global distribution of tectonic hazardsGlobal distribution of earthquakes, pacific Ring of Fire and alpine-Himalayan earthquake belt.Open →
• The hazard profile and magnitude scalesHazard profile, magnitude of a hazard and richter scale.Open →
• Types of volcano and styles of eruptionShield volcano, composite volcano and cinder cone.Open →
• Primary volcanic hazardsPrimary volcanic hazard, pyroclastic flow and lava flows as a hazard.Open →
• Secondary volcanic hazardsSecondary volcanic hazard, how a lahar forms and jökulhlaup and what triggers one.Open →
• Impacts of volcanic activity at local, regional and global scalesLocal-scale impact of volcanic activity, regional-scale impact of volcanic activity and global-scale impact of volcanic activity.Open →
• Contrasting volcanic eruptionsTwo eruptions set against each other — the hazards each produced, who was exposed, and why the death tolls differed so sharply between a wealthy country and a poor one.Open →
• Earthquake characteristics and seismic wavesFocus of an earthquake, epicentre of an earthquake and P waves.Open →
• Ground shaking, liquefaction and landslidesHow ground shaking damages buildings, peak ground acceleration and why soft sediment increases earthquake damage.Open →
• Tsunami generation and impactsCommonest cause of a tsunami, how a tsunami travels across the deep ocean and run-up height.Open →
• Impacts of earthquakes in contrasting contextsThe same physical event in different places: primary and secondary effects, and why building standards, warning and emergency capacity matter more to the death toll than magnitude does.Open →
• Human factors affecting risk and vulnerabilityVulnerability in the context of a tectonic hazard, risk equation and pressure and Release model.Open →
• Monitoring, prediction and warningFour methods of monitoring a volcano, successful volcanic prediction and seismic hazard mapping.Open →
• Mitigation and the hazard management cycleFour stages of the hazard management cycle, modifying the event and lava flow being diverted.Open →

What you need to know

Answer each one before you reveal it.

Take Tectonic Hazards further

The same content, four other ways.

Commonly confused

Pairs that lose marks when they are blurred together.

• Prediction vs Forecasting

  Prediction: stating the time, place and size of a hazard event. Forecasting: giving only a probability over a period.

• Ridge push vs Slab pull

  Ridge push: gravitational sliding away from an elevated spreading axis. Slab pull: a sinking cold plate edge dragging the rest behind it.

• Hazard vs Disaster

  Hazard: a physical event with the potential to harm. Disaster: the harm that follows when it meets a vulnerable population.

Questions from this topic

Each one with the model answer underneath.

1. 1

   Name the four main layers of the Earth's interior, from the surface inwards.

   Model answer

   The crust, the mantle, the outer core and the inner core make up the interior. The crust and uppermost mantle together form the rigid lithosphere.

2. 2

   What is the Moho, and where does it lie?

   Model answer

   The Mohorovičić discontinuity, or Moho, marks the boundary between the crust and the mantle. Depth ranges from around 5 km under oceans to 70 km under mountain belts.

3. 3

   State the depth of the Gutenberg discontinuity and what it separates.

   Model answer

   The Gutenberg discontinuity lies at a depth of about 2,900 km. The boundary separates the solid lower mantle from the liquid outer core.

4. 4

   Which discontinuity separates the outer core from the inner core?

   Model answer

   The Lehmann discontinuity separates the liquid outer core from the solid inner core, at about 5,150 km depth. Pressure there is high enough to keep the iron-nickel inner core solid.

5. 5

   Contrast the density and composition of oceanic and continental crust.

   Model answer

   Oceanic crust is basaltic and dense, at roughly 3.0 g cm⁻³, and only 5–10 km thick. Continental crust is granitic and lighter, around 2.7 g cm⁻³, and 30–70 km thick.

6. 6

   Why is oceanic crust much younger than continental crust?

   Model answer

   Oceanic crust is created at ridges and destroyed at subduction zones, so none is older than about 200 million years. Continental crust is too buoyant to subduct and survives for billions of years.

What is inside Levo

Six ways to work the same material.

Tectonic Hazards revision questions

What does Tectonic Hazards cover in Eduqas A-Level Geography?

18 subtopics: earth's internal structure and plate movement, divergent plate margins, convergent margins, subduction and collision, conservative margins and hot spots, global distribution of tectonic hazards, the hazard profile and magnitude scales, types of volcano and styles of eruption, primary volcanic hazards, secondary volcanic hazards, impacts of volcanic activity at local, regional and global scales, contrasting volcanic eruptions, earthquake characteristics and seismic waves, ground shaking, liquefaction and landslides, tsunami generation and impacts, impacts of earthquakes in contrasting contexts, human factors affecting risk and vulnerability, monitoring, prediction and warning and mitigation and the hazard management cycle. Each one has its own page with questions and model answers.

How is Tectonic Hazards organised?

By the Eduqas A110QS specification, subtopic by subtopic, so it matches the order you are taught it in.