Topic 1: 1.8 There are different plate boundaries, each with characteristic volcanic and earthquake hazards — Edexcel GCSE Geography B
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Topic 1: 1.8 There are different plate boundaries, each with characteristic volcanic and earthquake hazards explained
Topic 1: 1.8 There are different plate boundaries, each with characteristic volcanic and earthquake hazards covers 2 specification points, including A.
Read the full explanation
Distribution and characteristics of the… and B. Causes of contrasting volcanic (volcano…. Open a point below for its explanation and revision guidance.
a. Distribution and characteristics of the three plate boundary types (conservative, convergent and divergent) and hotspots.
This statement asks you to describe where the three plate boundary types and hotspots are distributed and what each is like. Conservative boundaries have plates sliding past each other, causing shallow earthquakes but little volcanism, as at the San Andreas Fault. Convergent boundaries have plates colliding; where oceanic crust meets continental crust, the denser oceanic plate subducts, producing volcanoes and deep earthquakes, as in the Andes. Divergent boundaries have plates moving apart and magma rising to fill the gap, as along the Mid-Atlantic Ridge. Hotspots are relatively fixed areas of volcanism within plates, produced by rising mantle plumes rather than by boundaries, as at Hawaii. Give location and features for each.
b. Causes of contrasting volcanic (volcano type, magma type/lava flows and explosivity) and earthquake hazards, including tsunami (shallow/deep, magnitude).
Contrasting tectonic hazards arise from different causes. Basaltic magma is low in silica, very hot and runny, so it forms gentle effusive lava flows and shield volcanoes such as Mauna Loa. Andesitic and rhyolitic magma is high in silica and viscous, trapping gas so pressure builds and eruptions are explosive. Shallow-focus earthquakes, usually within about 70 km of the surface, cause more damage than deep-focus events, whose energy is released far below ground. Magnitude measures energy on a logarithmic scale, so each whole-number increase releases roughly 32 times more energy. Tsunamis form when a large, shallow undersea earthquake displaces the seabed and pushes the water column upward.
Your focus
- Name the three plate boundary types and hotspots.
- Describe the characteristic movement, hazards and features of each boundary type.
- Match a named global example to the correct boundary type or hotspot.
Show all 6 objectives
- Explain how magma silica content and viscosity determine volcano type and explosivity.
- Compare how focus depth and magnitude influence the hazard produced by an earthquake.
- Describe how a large, shallow undersea earthquake can generate a tsunami.
Topic 1: 1.8 There are different plate boundaries, each with characteristic volcanic and earthquake hazards exam tips
Marking Points
- Locates each boundary type with an accurate global example, such as the San Andreas Fault for conservative boundaries.
- Explains that conservative boundaries involve plates sliding past each other, producing shallow earthquakes with little volcanism.
- Describes convergent boundaries as collisions where subduction produces volcanoes and deep earthquakes.
- Describes divergent boundaries as plates separating, with magma rising to create new crust along ridges such as the Mid-Atlantic Ridge.
- Recognises that hotspots occur within plates above mantle plumes and are independent of plate boundaries.
- Explains that basaltic magma is low in silica and runny, producing gentle effusive lava flows and shield volcanoes.
- Explains that andesitic and rhyolitic magma is viscous, trapping gas so that pressure builds and eruptions are explosive.
- Links focus depth to surface damage by stating that shallow-focus earthquakes release energy closer to the surface.
- Describes magnitude as a logarithmic measure of energy released, separate from the damage caused at a given location.
- Describes tsunami formation from vertical displacement of the seabed by a large, shallow undersea earthquake.
Examiner Tips
- 💡Link each boundary type to its direction of plate movement and one named example.
- 💡Treat hotspots as a separate category when a question asks about them, not as a boundary.
- 💡Describe features such as earthquake depth or volcanic activity, not just the boundary name.
- 💡Read every option against the full statement, checking whether it names a cause (magma, viscosity, focus depth, magnitude or seabed displacement) rather than a consequence.
- 💡Eliminate options that swap magma types or confuse magnitude with damage, because these are the most common distractors for this topic.
- 💡When two options both seem correct, choose the one that links the cause to the hazard type it produces, such as viscosity to explosivity.
Common Mistakes
- Confuses conservative with divergent boundaries by describing plates moving apart; recall that conservative boundaries involve lateral sliding.
- Treats hotspots as a type of plate boundary; state that hotspots sit within plates above mantle plumes.
- Gives an example that does not match its boundary type, such as placing the Andes at a mid-ocean ridge; match each example to its type.
- Confuses magnitude with intensity; state that magnitude measures energy released, while damage depends on local conditions.
- Describes shallow and deep focus as equally damaging; correct this by explaining that shallow events transmit energy closer to people and buildings.
- Links all volcanoes to explosive eruptions; explain that basaltic magma usually produces effusive flows, whereas silica-rich magma tends to be explosive.
- Attributes tsunamis to any earthquake; specify a large, shallow undersea earthquake that moves the seabed vertically.