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Tectonic Hazards

infoWhy this? Tectonic hazards reveal how processes within the Earth create patterned but potentially devastating events at the surface. Understanding plate movement, vulnerability, and risk reduction enables us to explain why impacts vary and how prediction, protection, and preparation can make communities more resilient.

scheduleWhy now? After studying atmospheric and coastal systems, we are ready to investigate a contrasting set of large-scale physical processes within the Earth. The unit applies global mapping, case-study evidence, and evaluative skills while establishing a hazard framework that will support later work on flooding and extreme weather.

neurologyYou need to know

  • A natural hazard is a natural event that can cause harm to people, property, or the environment, and it becomes a disaster when it causes serious impacts on people.
  • Tectonic hazards are caused by movements of tectonic plates and include earthquakes, volcanic eruptions, and tsunamis.
  • Tectonic hazards are not randomly distributed because they occur mainly along tectonic plate boundaries.
  • The Pacific Ring of Fire is the main global zone where earthquakes and volcanoes occur most frequently.
  • The Earth has four main layers: the crust, mantle, outer core, and inner core.
  • The crust is the thin, solid outer layer of the Earth and forms the upper part of tectonic plates.
  • The mantle is a thick, mostly solid layer beneath the crust.
  • The outer core is liquid, the inner core is solid, and both are extremely hot layers at the centre of the Earth.
  • Tectonic plates are rigid slabs of lithosphere comprising the crust and uppermost mantle, and they move over the weaker, mostly solid asthenosphere.
  • Mantle convection is extremely slow solid-state flow driven by the Earth's internal heat, in which warmer material rises and cooler material sinks, helping to move tectonic plates.
  • Major tectonic plates include the Pacific Plate, North American Plate, Eurasian Plate, and Indo-Australian Plate, and the Pacific Plate is the largest.
  • The three main types of plate boundary are constructive, destructive, and conservative boundaries.
  • At constructive plate boundaries, plates move apart, magma rises to create new crust, and volcanoes and earthquakes can occur.
  • At destructive plate boundaries, plates move towards each other, one plate is forced beneath another, and strong earthquakes and explosive volcanoes can occur.
  • At conservative plate boundaries, plates slide past each other, causing earthquakes but not volcanoes.
  • An earthquake is caused by the sudden movement of tectonic plates, which releases energy as seismic waves.
  • The focus is the point inside the Earth where an earthquake starts, and the epicentre is the point on the Earth's surface directly above the focus.
  • The Richter scale measures earthquake magnitude, which means the strength or energy released by an earthquake.
  • The 2010 Haiti earthquake occurred on 12 January 2010 at a conservative plate boundary between the Caribbean Plate and the North American Plate.
  • The 2010 Haiti earthquake was especially damaging because it was shallow, about 13 km deep, and Haiti had high vulnerability due to weak buildings, poverty, and limited infrastructure.
  • Hazard impacts can be reduced through prediction, protection, and preparation.
  • Tectonic hazard prediction involves monitoring warning signs; earthquakes are hard to predict, but volcanoes can sometimes be monitored.
  • Protection includes building design and technology to reduce damage from tectonic hazards.
  • Preparation, such as education, drills, and emergency planning, helps people respond effectively to tectonic hazards and save lives.

rocket_launchYou must be able to

  • Define a tectonic hazard accurately by linking it to plate movement and its potential to cause harm to people.
  • Locate the main global distribution of tectonic hazards on a world map, especially along plate boundaries and around the Pacific Ring of Fire.
  • Label and describe the four layers of the Earth, including the crust, mantle, outer core, and inner core.
  • Explain plate movement as rigid slabs of lithosphere moving over the weaker asthenosphere, driven partly by extremely slow solid-state mantle convection caused by the Earth's internal heat.
  • Compare constructive, destructive, and conservative plate boundaries by describing plate movement and the hazards produced at each one.
  • Annotate an earthquake diagram with the focus, epicentre, and seismic waves in the correct positions.
  • Explain the causes and impacts of the 2010 Haiti earthquake using named plates, boundary type, depth, and evidence such as deaths and homelessness.
  • Compare shield and composite volcanoes by referring to lava viscosity, eruption style, and volcano shape.
  • Suggest ways to reduce tectonic hazard risk by applying prediction, protection, and preparation to a named place or scenario.


Revision Quiz

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