1.3

Question 1

What are P Waves?

Answer 1

P (primary) waves caused by compression pushing and pulling in the direction of travel (pulsing
These are the fastest and first to arrive

Question 2

What are S Waves?

Answer 2

S (secondary) waves are slower

These waves only move through solid rock in an up and down movement.

Question 3

What are L Waves?

Answer 3

L (Love) waves only travel through the surface of the crust. Fastest surface wave. Moves from side to side as it moves forward. Causes most damage due to longer wavelength and focus of energy at the surface.

Question 4

What are seismic waves

Answer 4

primary, secondary, love from the hypo centre in a circular motion from the focus

Question 5

What is the hypo centre/focus?

Answer 5

The point at which friction and energy is released from in the ground

Question 6

What is a fault?

Answer 6

a fissure/line that is between plates/boundary

Question 7

What is an epicentre?

Answer 7

the point on the surface directly above the focus

Question 8

What factors the severity of an earthquake?

Answer 8

magnitude = how much energy
distance from focus/epicentre = impact over time
bedrock/soil = saturated area (liquefaction?)

Question 9

What is the difference between primary and secondary hazards?

Answer 9

primary = shaking and crustal fracturing (initial)
secondary = ‘side-effects’ of primary hazards
-> tsunamis, landslides

Question 10

Why is it difficult for buildings to stay intact during an earthquake?

Answer 10

• more than one type of waves
• can cause secondary problems (liquefaction, landslides)
• waves can destroy buildings quickly eg L waves

Question 11

What is liquefaction?

Answer 11

liquefaction = loosely packed sand becomes saturated as water takes up pore spaces.
Causes loss of bonds making solids act like water
Causes buildings structure to fail

Question 12

What are landslides?

Answer 12

When slope processes cause mass movements and therefore, areas to collapse due to the pressure and energy.
Can be natural
Earthquakes over 4 are more likely to cause these mass movements

Question 13

What are the types of volcanoes?

Answer 13

Composite and shield volcanoes

Question 14

What are some characteristics of a composite volcano?

Answer 14

cone volcanoes have form from viscous lava that is rhyolitic and andesitic so is quite runny and flows without building layers
These are ususally at sub-duction zones
These are steep sided
And more likely to have pyroclastic flows

Question 15

What are some characteristics of a shield volcano?

Answer 15

form from lava with low viscoity basaltic so it cant run and forms layers.
This usually happens as hotspots and mid ocean ridges
These are less steep and very wide

Question 16

What are the 3 types of lava?

Answer 16

basaltic
andesitic
rhyolitic

Question 17

What is basaltic lava?

Answer 17

hottest (1000-1200c)
mostly CO2, Fe,Mg
low gas content
materials melting from upper mantle
thin and runny
low viscosity
gently effusive
hot spots, ridges, shield volcanoes

Question 18

What is andesitic lava?

Answer 18

800-1000C
intermediate silica 
3-4% gas content
subducted oceanic plates + seawater
slow movement
violent 
somewhat explosive
composite volcanoes and subduction zones

Question 19

What is rhyolitic lava?

Answer 19

650-800C 
cataclysmic
supervolcanoes or composite cone volcanoes
highest silica content 70%
4-6% gas
melting of lithospheric mantle and slabs
thick and stiff
viscous

Question 20

What is the runniest and thickest lava?

Answer 20

runniest = basaltic
thickest = rhyolitic

Question 21

What are primary hazards of a volcano?

Answer 21

Lahars, acid rain, ash flow, fumeroles, fire, pyroclastic flows, landslides - debris avalanche,

Question 22

What are secondary hazards of a volcano?

Answer 22

volcanic bombs, ash cloud (tephra fall), lava, pyroclastic flows, jokulhlaups

Question 23

Where do volcanoes occur?

Answer 23

convergent margins with oceanic + continental
divergent either
hot spots

Question 24

What are lahars, fumeroles, jokulhaups, pyrolastic flows, tephra?

Answer 24

Lahars = mudflow because of heat and destabilisation
fumeroles = gas from volcano released
jokulhaups = type of glacial outburst flood because of heat and eruption
pyroclastic flows = fast moving lava or gas
tephra = rock ejected from a volcano

Question 25

What is a tsunami?

Answer 25

an abnormal wave that is greater than average due to previous tectonic activity and can cause major damage as a secondary hazard

Question 26

What are features of a tsunami and how are they formed?

Answer 26

they have long wavelength (150-1000km)
low height towards the coast (0.5-5m)
come as a series (train)
fast velocity up to 600kph
formed = volcanic eruptions and landslides, destructive boundary where continental flips upwards 
90% on pacific basin

Question 27

Where are the high risk zones?

Answer 27

along coastal countries like america, eastern asia, japan,

Question 28

How are tsunami waves formed by earthquakes?

Answer 28

when there is subduction and build of elastic and continental builds up tectonic strain causing release of energy. This releases energy in a water column displacement as mega thrust to upwell.
This is released as a series of waves

Question 29

What is a water column displacement?

Answer 29

its is a direct vertical upwards of water straight to the surface the energy therefore carries on throughout in a circle eg indian ocean 2004

Question 30

What are the main features of an volcano?

Answer 30

Magma chamber
Conduit/pipe
Vent
Dome

Question 31

How does liquefaction effect buildings after and before?

Answer 31

Before : loosely packed grains are held by friction and filled with water in pore spaces

After : shaking destabilises the soil by increasing space between grains. With this structure lost it flows like a liquid

Question 32

Describe one secondary hazard associated with earthquakes?

Answer 32

tsnuamis - wavelength, water displacement column
Liquefaction - removes solidity of particles move like a liquid
Landslides - from disturbed particles

Question 33

What are 4 primary hazards of volcanic hazards?

Answer 33

Ash
Pyroclastic Flows
Volcanic bombs
Volcanic gases

Question 34

Are volcanic eruptions a unique natural hazard?

Answer 34

YES = more predictable (eg water turns brown, gas samples, longer duration (active volcanoes many years eg Hawaii) therefore, evacuation takes longer, only hazard with visible magma and can see what is beneath the surface.

Question 35

What are 4 secondary hazards from a volcanic eruption?

Answer 35

acid rain, jokulhaups, landslides, lava flows, ash flows, fumeroles, lahars