Earthquakes

Question 1

Where are the main earthquake zones

Answer 1

Clustered along plate boundaries

Question 2

What does e/q mean

Answer 2

EARTHQUAKE

Question 3

Which plate boundaries are associated with e/q

Answer 3

Conservative and destructive boundaries — but can occur at all boundaries

Question 4

Why might an earthquake occur within the plates (intra-plate)

Answer 4

Due to ancient faults which solid crust cracks over millions of years

Question 5

How are earthquakes created within the destructive plate boundaries

Answer 5

any plate boundary stress and strain can build up along the joint, due to friction created by masses of rock trying to move past each other.

This is greatest along the wadati-benioff zone within destructive plate boundaries

Question 6

conservative boundary earthquake characteristic

Answer 6

sliding
no volcanoes
earthquakes are violent
no crust is made or destroyed
Stress is also great along transform (conservative) boundaries

Question 7

what is a focus of an earthquake

Answer 7

the point of which the strain is released this sends earthquake (seismic)

Question 8

what is the epicentre of an earthquake

Answer 8

waves in all directions being the strongest at the point on the earth’s surface directly above the focus

Question 9

What are the 4 earthquake waves

Answer 9

P waves - primary waves
S waves - secondary waves
Love waves
Rayleigh waves

Question 10

What is a P wave

Answer 10

primary wave
Body wave (go through the earth)
They are the fastest and first to reach the surface
Travel through both solid and liquids
Only damaging in the most powerful earthquakes

Question 11

What is a S wave + its characteristics

Answer 11

secondary wave
slower than a P wave (by 60%)
Only travel through solid
they do more damage than P wave

Question 12

what is a L wave

Answer 12

Love wave
the slowest (last to arrive)
cause the most shaking (from side to side)
they are larger and focus all their energy on the surface
cause the most damage

Question 13

TRUE OR FALSE:
is Rayleigh wave a surface wave

Answer 13

TRUE

Question 14

what two characteristics do scientists use to measure earthquakes

Answer 14

magnitude and intensity

Question 15

what does magnitude measure

Answer 15

the amount of energy released at the epicentre.

Question 16

what does intensity measure

Answer 16

An earthquakes effect on people, infrastructure and the natural environment

Question 17

what scale is used to measure magnitude

Answer 17

MMS (moment magnitude scale)
one to infinite - generally stops at 10
logarithmic scale
e.g 9.5 in chile 1960

Question 18

what scale is used to measure intensity of e/q

Answer 18

the modified Mercalli intensity scale

scale of 1 (hardly noticeable) to X (catastrophic)

Question 19

What does MMS use to calculate rating

Answer 19

Size of seismic waves
Amount of slippage or rock movement
Area of the faults surface broken by the e/q
Resistance of the affected rocks

Question 20

The physical effects of an earthquake

Answer 20

Magnitude
Depth
Distance from the epicenter

Question 21

The human effects of an earthquake

Answer 21

-Countries level of development
-Population
-Level of preparedness
-Effectiveness of emergency responses
-Impact of indirect hazards (fire and landslides

Question 22

Define a primary effect for e/q

Answer 22

those that happen as a direct result of an earthquake

Question 23

Define secondary effect for e/q

Answer 23

those that happen after the initial shaking

Question 24

What is a primary effect of an earthquake

Answer 24

Ground shaking – which causes building, bridges roads and infrastructure to collapse – killing and injuring those nearby

Crustal fracturing – when the energy released during the earthquake causes the Earth’s crust to crack

Question 25

What is a secondary effects of an earthquake

Answer 25

-Liquefaction
-Landslides and avalanches
-Tsunami

Question 26

What is liquefaction

Answer 26

The violent shaking causes surface rocks to lose strength and become more liquid than solid.

Question 27

How can liquefaction effect

Answer 27

It can make rescue efforts more difficult and also disrupt underground power and gas lines (leading to fires)

Question 28

when do landslides occur

Answer 28

when e/q’s loosen loose rocks and unconsolidated material on steep slopes causing material to move downwards, influenced by gravity

Question 29

what can landslides lead to in regards to people

Answer 29

landslides may hit small settlements within its topography and…
-block or destroy roads and railways
-making it difficult to rescue people or supply emergency aid and rebuilding materials

Question 30

example of landslides

Answer 30

Nepal 2015, Kashmir 2005