Chapter 1 - Locations At Risk From Tectonic Hazards Flashcards Preview

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Flashcards in Chapter 1 - Locations At Risk From Tectonic Hazards Deck (18)
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1
Q

Seismic hazards

A

Generated when rocks in the earths surface come under stress so they break and become displaced

2
Q

Volcanic hazards

A

Associated with eruption events

3
Q

Intra-plate earthquakes

A

These occur in the middle or interior of tectonic plates, rarer than boundary earthquakes

4
Q

Volcano

A

Landform that develops around a weakness in the earths crust from which molten magma, volcanic rock and gases are ejected or extruded

5
Q

Divergent boundary

A
  • constructive
  • mid-ocean ridges
  • large numbers of shallow focus and low magnitude earthquakes
  • most are submarine
6
Q

Convergent boundary

A
  • plates are moving together
  • actively deforming collision locations
  • plate material melts in the mantle
  • frequent earthquakes & volcanoes.
7
Q

Lithosphere

A
  • surface layer of the earth, rigid outer layer composed of the crust and upper mantle.
  • very thick
  • always moving, but very slowly, fuelled by rising heat from mantle, creates convection currents
  • broken into huge sections which is tectonic plates
8
Q

Plate tectonics

A

Theory developed to explain large scale movements of the lithosphere.

9
Q

Volcanic hotspot

A

Area in the mantle from which heat rises as a hot thermal plume from deep in the earth.

10
Q

Paleomagnetism

A

Results from the zone of magma locking in or striking the Earth’s magnetic polarity when it cools. Can be used to create a geo timeline

11
Q

Benioff zone

A

An area of seismicity corresponding with the slab being thrust downwards in a subduction zone

12
Q

Locked fault

A

A fault that is not slipping because the frictional resistance on the fault is greater than the shear stress across the fault, so it’s stuck

13
Q

Hypocentre

A

The focus point within the ground where the strain energy of the earthquake stored in the rock is first released.

14
Q

Soil liquefaction

A

The process by which water-saturated material can temporarily lose normal strength and behave like a liquid under the pressure of strong shaking

15
Q

Intensity

A

A measure of the ground shaking. Ground shaking is what causes building damage and deaths.

16
Q

Magnitude

A

Related to the amount of movement or displacement at the fault, is in turn a measure of energy

17
Q

Epicentre

A

The location on the earths surface that is directly above the earthquakes focus

18
Q

Tsunami

A

Tsu (port or harbour) nami (wave or sea). Initiated by undersea earthquakes.

  • long wavelengths
  • low amplitude
  • fast velocities