Characteristics of earthquakes caused by varying types of plate margin movement and human triggers and associated secondary hazards

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distinguish between the focus and epicentre

the focus is the point where the seismic waves originate from whilst the epicentre is the point on the surface directly above the focus

how does the depth of the focus affect the nature of an earthquake

shallow focus earthquakes do more damage because there is not as much of an opportunity for energy to be lost

what type of waves are P and S waves

body wave

what type of wave are P waves in the context of geophysics

longitudinal waves that shake the earth back and forwards

what type of wave are S waves in the context of geophysics

transverse waves that sway the earth from side to side. cannot move through liquids

what type of waves are love and rayliegh waves

surface waves

what type of wave are love waves in the context of geophysics

transverse waves that cause the earth to move side to side

what type of wave are rayleigh waves in the context of geophysics

longitudinal waves that cause the earth to move up and down

do body or surface waves do the most damage

surface

why do S waves do more damage than P waves

buildings cannot withstand horizontal stress which is caused by S waves

distinguish between the earthquakes caused by destructive, constructive, and conservative plate boundaries (3)

destructive plate boundaries have deep focus earthquakes as the oceanic plate is subducted, constructive plates have occasional mild earthquakes, conservative plates have shallow focus earthquakes

why can the construction of dams cause earthquakes

the additional weight of water can put stress on land and reactivate faults

give an example of an earthquake caused by dam building

the hoover dam caused 10000 small earthquakes near lake mead but only 1000 were felt by people

why can fracking cause earthquakes

the pressure caused by injecting fluid can destabilise rocks

give an example of an earthquake caused by fracking

a 4.4 magnitude earthquake in canada in 2014

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why are tsunamis caused

underwater earthquakes at subductive plate margins result in the continental plate flicking up and launching water forming a tsunami

why does soil liquefaction occur

loosely packed and waterlogged sediments are disrupted by shaking ground

why do landslides occur

shaking earth destabilizes ground