Option D • Section 1
Geophysical Systems
The processes creating earthquakes, volcanoes and mass movements—and the secondary hazards they generate.
Geophysical systems and the characteristics of geophysical hazards
Mechanisms of plate movement
Internal heat, mantle convection, ridge push and slab pull drive lithospheric plates.
Plate tectonics explains the broad global pattern of earthquakes and volcanoes. Different plate boundaries create different processes, landforms and hazard profiles; hot spots add important exceptions.
Build the explanation
Create a process diagram linking Earth’s internal heat to convection, ridge push, slab pull and plate motion. Apply it to constructive, destructive, collision and conservative margins, plus one hot spot.
Characteristics of volcanoes
Magma chemistry, gas, viscosity and tectonic setting shape eruption style and hazard.
Compare shield, composite and cinder-cone volcanoes. Primary hazards include lava, ash and pyroclastic density currents; secondary hazards include lahars, landslides and disruption far beyond the eruption zone.
Compare process and hazard
For two contrasting volcano types, link magma characteristics to shape, eruption style, primary hazards, secondary hazards and likely spatial reach.
Characteristics of earthquakes
Fault rupture releases energy as seismic waves; depth, magnitude, geology and distance affect shaking.
Distinguish focus from epicentre and magnitude from intensity. Secondary hazards—tsunami, liquefaction, landslides, fire and infrastructure failure—may cause more damage than shaking alone.
Cascading-hazard map
Begin with fault rupture and build pathways to shaking, liquefaction, landslide, tsunami, fire and service failure. Label the physical condition required for each branch.
Classification of mass movements
Falls, slides and flows vary by material, movement, speed and water content.
Gravity is the driving force, while triggers include saturation, earthquakes, undercutting, weathering and human slope modification. Classification helps predict mobility, warning time and management options.
Create a classification key
Classify eight examples by material, movement, speed and moisture. For each, identify one preparatory factor, one trigger and one likely secondary impact.