Key Terms Flashcards
Asthenosphere
The upper mantle layer 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
Benioff Zone
A region of the subducting plate, most affected by pressure and friction, where most destructive margin earthquakes origionate
Continental Crust
Crust that forms the continents of the lithosphere, approximately 35km thick.
Continental Drift
The movement of tectonic plates, due to varying weights of crust. It was origionally 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 asthenosphere. Magma is heated by radioactive processes in the core and cools at the surface , and so circulates between the two plates.
Coriolis Effect
The Earth’s spin affects the movement of air masses and winds, depending on a locations latitude.
Crown fires
Wildfires that burn the entirety of a tree (from top to bottom), often the most destructive and dangerous type of wildfire.
Park Model
This model shows how quality of life is affected by any hazardous event.
Epicentre
The point on the surface, directly above the earthquakes 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 mitigaiton
Hot Spot
Volcanoes found away from the plate boundary, due to a magma plume closer to the surface
Jokulhlaups
Sudden glacial floods caused by a glacier on top of or near a volcano melting due to the heat from eruption.
Lahar
A flow of water, mud and debris
Lithosphere
The upper crust of the Earth, average thickness of 100km
Mid-Ocean Ridge
Parting oceanic plates at a constructive plate boundry 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 at the sea floor. 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 alernate over thousands of years
Park’s Model
A model describing the decline and recovery of a country over time, following a natural disaster
Primary Waves
An earthquake wave causing compressions within the body of a rock
Pyroclastic Flow
A mixture of gases and rock fragments, at high temperatures travelling at rapid speeds
Richter Scale
A logarithmic measuire of earthquake’s intensity
Secondary Waves
An earthquake wave causing vertival displacement within the body of the rock
Seismic Waves
The energy released during an earthquake, in the form of Primary, Secondary, Love and Rayleigh waves
Slab Pull
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 (due to the coiolis effect). Called Hurricanes, Cyclones and Typhoons
Tsunami
Initial vertical water displacement (often from a submarine earthquake) creates waves, with large destructive power.
Volcanic Explosivity Index (VEI)
A meaure of the magnitude of a volcano’s eruptions
Volcanic Island Arc
A series of volcanoes (often in the shape of an arc) that are formed consecutively, as a tectonic plate moves across a magma plume
Wildfire
A large, uncontrolled fire that quickly spreads through vegetation