Hazards BK 4 - Seismic Hazards

Question 1

what are 3 types of seismic hazards

Answer 1

earthquakes , tsunamis and aftershocks

Question 2

what are 2 primary impacts of a seismic hazard

Answer 2

shaking of the ground
deformation

Question 3

what is deformation

Answer 3

changing of the earths surface due to a seismic hazard

Question 4

what are some secondary impacts of seismic hazards

Answer 4

mass movement
flooding
death/injury
evacuation
homelessness
fires
liquefaction

Question 5

what is the definition of focus

Answer 5

the point where the pressure released from an earthquake occurs in the crust, where shockwaves radiate from

Question 6

what is the definition of epicentre

Answer 6

the point immediately above the focus

Question 7

which focus earthquake causes the most damage

Answer 7

shallow focus

Question 8

what are the two main types of wave

Answer 8

body and surface

Question 9

what are body waves

Answer 9

they transmit much of their energy deep underground

Question 10

what are surface waves

Answer 10

waves that vibrate through the earths crust creating destructive surface waves

Question 11

what are the two types of body waves

Answer 11

P waves and S waves

Question 12

what are some factors of P waves

Answer 12

fast moving
cause rock to expand and contract
travel through liquids and solids, so can pass through the centre of the earth
cause little destruction

Question 13

what are some factors of s waves

Answer 13

slower moving and can’t pass through liquid
exert force up and down
these waves can be destructive

Question 14

what are the two types of surface waves

Answer 14

love waves
rayleigh waves

Question 15

what are some factors of love waves

Answer 15

they cause the ground to shake from side to side
cause a lot of damage and destruction

Question 16

what are some factors of rayleigh waves

Answer 16

very destructive
ground moves forwards and backwards and up and down too

Question 17

how fast do P and S waves tend to travel

Answer 17

P= 6km per minute
S= 3km per minute

Question 18

do the british isles still get earthquakes?

Answer 18

yes but they’re very small so mostly aren’t felt by anybody

Question 19

what 3 ways are earthquakes measured

Answer 19

the richter scale
the moment magnitude scale
the mercalli scale

Question 20

why are some scientists concerned about the richter scale

Answer 20

it was not developed to allow for accurate measurements of deeper focus quakes but it has been adapted.

Question 21

what scale is now used by seismologists instead of the richter scale

Answer 21

the moment magnitude scale

Question 22

whats the moment magnitude scale mkre reliable in measuring

Answer 22

measuring larger scale earthquakes more accurately

Question 23

what scale does the richter scale measure to and from

Answer 23

1-9

Question 24

what is the mercalli scale based on

Answer 24

the intensity of an earthquake as measured by the damage that it causes, in terms of the visual observation of effects

Question 25

how many numbers does the mercalli scale go too

Answer 25

12

Question 26

what are some impacts of seismic hazards

Answer 26

fires shockwaves tsunamis soil liquefaction mass movement damage to infrastructure

Question 27

what determines the severity of the ground shaking due to an earthquake

Answer 27

magnitude depth distance from epicentre local geological conditions

Question 28

what’s the definition of ground rupture

Answer 28

the visible breaking and displacement of the earths surface, usually along a line or fault

Question 29

what two things does ground displacement involve

Answer 29

uplift and subsidence

Question 30

what is liquefaction

Answer 30

when soil is shaken violently and takes on the properly of a liquid

Question 31

what damage can liquefaction cause

Answer 31

infrastructure to collapse uproot trees damage to underground pipes

Question 32

why do fires tend to follow earthquakes in urban areas more than rural ones

Answer 32

more gas pipes and electrical systems in urban areas

Question 33

what is a tsunami

Answer 33

a giant sea wave generated by shallow focus underwater earthquakes, volcanic eruptions and large landslides into the sea

Question 34

what are some factors of tsunamis

Answer 34

long wavelength low wave height height increases nearer the shore

Question 35

what is the first warning of a tsunami

Answer 35

reduction in sea level at the shoreline

Question 36

what are 8 techniques that can be used to manage seismic hazards

Answer 36

1)hazard resistant structures 2)education 3)fire preventation 4)emergency services 5)land use planning 6)insurance 7)aid 8)Building preparedness

Question 37

how do hazard resistant structures work

Answer 37

1)large concrete weight ontop of building so it moves in opposite direction 2)large rubber shock absorbers in foundations 3)cross bracing to structure to hold it together when it shakes

Question 38

how does education of seismic hazards work

Answer 38

authorities tend to give out instructions about how to prepare for these hazards , earthquake evacuation at school etc

Question 39

how does fire preventation management work

Answer 39

smart meters that have been made will be cut off in event of a high magnitude earthquake

Question 40

how does emergency services work in terms of the management of a seismic event

Answer 40

heavy lifting gear always available first aid trained people

Question 41

how does land use planning work in terms of managing a seismic event

Answer 41

help understand which areas are most and least at risk areas can be grouped

Question 42

how does insurance work in terms of managing a seismic hazard

Answer 42

more affluent areas see rich take out and invest in insurance to cover their losses very expensive

Question 43

how does aid work in terms of managing a seismic event

Answer 43

poorer countries tend to receive more aid e.g. medical support, tents etc

Question 44

how does building preparedness work in terms of managing a seismic event

Answer 44

buildings and homes made using light walls, straw, bamboo to reinforce walls better than having light roofs which can easily fall or collapse