Hazards

• Accretion Wedge


  The accumulation of material at the point of subduction
• Aseismic Buildings


  Buildings designed to withstand or minimise destruction during an earthquake
• Asthenosphere


  The upper mantle of the Earth. It is semi-molten and approximately 2000km wide
• Ash 


  Fine particles and dust ejected during an eruption, which can remain airborne as clouds or accumulate on the ground
• Continental Crust


  Crust that forms the continents of the lithosphere, on average 35km thick
• Continental Drift


  The movement of tectonic plates, due to varying weights of crust. It was originally thought that convection currents caused the movement of the plates, but now slab pull is thought of as the primary driving force
• Controlled Burning


  Intentionally burning vegetation with the aim of reducing fuel available for a wildfire and disrupting the fire's path
• Convection Currents

  The circulation of magma within the mantle. Magma is heated by radioactive processes in the core and cools at the surface, and so circulates between the two places
• Coriolis Effect


  The Earth's spin affects the movement of air masses and winds, depending on the location's latitude
• Crown Fires


  Wildfires that burn the entirety of a tree, often the most destructive and dangerous type of wildfire
• Degg's Model


  This model shows that a hazard becomes a disaster if it affects a vulnerable population
• Epicentre


  The point on the surface, directly above the earthquake's origin
• Fatalism


  The belief that hazards are uncontrollable, so any losses should be accepted and mitigation is unnecessary
• Fire Breaks


  The felling of trees and clearing vegetation to create a gap to disrupt a wildfire's path
• Focus


  The place in the crust where the pressure/seismic energy is released
• Ground Fires


  Wildfires that burn through the peat and vegetation beneath the surface, making them slow but difficult to extinguish
• Hazard Management Cycle


  The sequence of governance of a natural hazard: preparedness, response, recovery, and mitigation
• Hot spot

  Volcanoes found away from the plate boundary, due to a magma plume closer to the surface
• Jokulhaup


  A sudden glacial flood caused by a glacier on top of or near a volcano melting due to the heat from the eruption
• Lahar


  A flow of mud and debris
• Lithosphere


  The upper crust of the Earth
• Love Waves


  A surface earthquake wave with horizontal displacement
• Mid-Ocean Ridge


  Parting oceanic plates at a constructive plate boundary creates a ridge, with new land at the base of the oceanic valley
• Moment Magnitude Scale


  A measure of an earthquake's energy released, considered the most accurate measure
• Oceanic Crust


  Crust, usually thinner than continental crust, that forms the sea level. It is on average 7km thick
• Paleomagnetism


  The alternating polarisation of new land created. As magma cools, the magnetic elements within will align with the Earth's magnetic field, which can alternate over thousands of years
• Park's Model


  A model describing the decline and recovery of a country over time, following a natural disaster
• Partial Melting


  Elements within the lithosphere have different melting points, and so rock is partially melted, partially solid.
• Primary waves


  An earthquake wave causing compressions within the body of rock
• Pyroclastic flow


  A mixture of gases and rock fragments, at high temperatures travelling at rapid speeds
• Rayleigh waves


  A surface earthquake wave causing both horizontal and vertical displacement
• Richter scale


  A logarithmic measure of earthquake's intensity
• Secondary Waves


  An earthquake wave causing vertical displacement within the body of rock
• Seismic waves


  The energy released during an earthquake, in the form of Primary, Secondary, Love and Rayleigh waves
• Slab pul


  The force contributing to the movement of tectonic plates. Slab pull is due to the weight of the plate
• Subduction

  Oceanic plate is forced below continental plate, due to the oceanic plate being more dense than the continental plate
• Surface Fires


  Wildfires that only burn the leaf litter, and so are the easiest kind to extinguish
• Tropical Storm


  A low pressure system of spiralling winds. Also called hurricanes, cyclones, and typhoons depending on the location they occur in
• Tsunami


  Initial vertical water displacement creates waves, with large destructive power
• Volcanic Explosivity Index (VEI)


  A measure of the magnitude of a volcano's eruptions