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neurologyYou need to know

• The Earth’s basic internal structure includes the crust, mantle, outer core and inner core, and tectonic activity is mainly driven by processes in the lithosphere and asthenosphere.
• The lithosphere is the rigid outer layer of the Earth made up of the crust and the uppermost mantle, and it is broken into tectonic plates.
• The asthenosphere is the weaker, semi-molten part of the upper mantle beneath the lithosphere, allowing tectonic plates to move above it.
• Convection currents in the mantle transfer heat from the Earth’s interior and help drive the movement of tectonic plates.
• Continental drift is the theory that continents have moved over geological time from earlier positions, including the former supercontinent Pangaea.
• Evidence for continental drift includes the jigsaw fit of continents, matching fossil records across continents, matching rock types and mountain belts, and evidence of ancient glaciations in now-separated continents.
• Sea-floor spreading occurs at divergent plate boundaries where magma rises, cools and forms new oceanic crust, causing plates to move apart.
• Palaeomagnetism provides evidence for sea-floor spreading because magnetic minerals in oceanic crust record repeated symmetrical patterns of normal and reversed magnetic polarity on either side of mid-ocean ridges.
• The age of sea-floor rocks provides evidence for plate tectonics because oceanic crust is youngest at mid-ocean ridges and becomes older with increasing distance from the ridge.
• At divergent, or constructive, plate boundaries, plates move apart, magma rises to create new crust, and features include mid-ocean ridges, rift valleys, shield volcanoes and shallow-focus earthquakes.
• At oceanic-continental convergent, or destructive, plate boundaries, denser oceanic crust subducts beneath continental crust, forming ocean trenches, fold mountains, explosive volcanoes and earthquakes.
• At oceanic-oceanic convergent plate boundaries, one oceanic plate subducts beneath another, forming ocean trenches, island arcs, explosive volcanoes and earthquakes.
• At continental-continental collision boundaries, two continental plates collide and crumple to form fold mountains, with powerful earthquakes but little or no volcanic activity because neither plate subducts easily.
• At conservative plate boundaries, plates slide past each other laterally, producing shallow-focus earthquakes but no volcanic activity because crust is neither created nor destroyed.
• Explosive volcanic eruptions usually occur at convergent plate boundaries because silica-rich, high-viscosity magma traps gas and builds pressure before eruption.
• Effusive volcanic eruptions usually occur at divergent plate boundaries or hot spots because low-viscosity basaltic magma allows gases to escape and lava to flow more easily.
• The Volcanic Explosivity Index, or VEI, is a logarithmic scale used to measure volcanic eruption explosiveness based on factors such as volume of material erupted, eruption column height and eruption duration.
• Volcanic hazards include lava flows, pyroclastic flows, gas emissions, tephra and ash fall, lahars, flooding from melted ice and snow, and tsunamis caused by explosive eruptions or volcanic collapse.
• Earthquake hazards include ground shaking, ground displacement, liquefaction, landslides, avalanches, tsunamis caused by sea-bed uplift or underwater landslides, and flooding.
• Shallow-focus earthquakes occur close to the Earth’s surface and can cause severe damage, while deep-focus earthquakes occur deeper within subduction zones and usually affect wider areas but often with reduced surface intensity.

• Use geological, fossil, glacial and palaeomagnetic evidence to justify the theories of continental drift and plate tectonics.
• Compare divergent, convergent and conservative plate boundaries by linking plate movement to landforms, processes and hazards.
• Explain how magma viscosity, gas content and tectonic setting influence whether a volcanic eruption is explosive or effusive.
• Classify volcanic hazards as primary or secondary and explain how each hazard threatens people, infrastructure and environments.
• Compare earthquake magnitude and intensity measures, including the Richter scale, moment magnitude scale and modified Mercalli intensity scale, using their purpose and limitations.
• Analyse how earthquake processes generate hazards such as liquefaction, landslides, tsunamis and flooding.
• Evaluate the social, economic, environmental and political impacts of volcanic eruptions and earthquakes using case studies from countries at contrasting levels of development.
• Assess why people continue to live in tectonically active locations, considering benefits, risk perception, resources, culture, governance and economic constraints.
• Evaluate hazard management strategies by distinguishing between mitigation of the event, mitigation of vulnerability and mitigation of losses.
• Apply the disaster risk equation and the Park model to explain how exposure, vulnerability, capacity, response and recovery influence the scale of tectonic disasters over time.