1.3 Earthquakes

Question 1

where do 95% of earthquakes occur?

Answer 1

along plate boundaries

Question 2

where do 5% of earthquakes occur?

Answer 2

intra-plate

Question 3

how is energy released during an earthquake?

Answer 3

seismic waves

Question 4

where is pressure released from during an earthquake?

Answer 4

the hypocentre

Question 5

where is the epicentre located?

Answer 5

the earth’s surface directly above the hypocentre

Question 6

where does most damage occur during an earthquake?

Answer 6

the epicentre

Question 7

what are the 3 types of seismic waves?

Answer 7

P waves
S waves
L waves

Question 8

describe P waves
(3 points)

Answer 8

move the fastest
reach the earth’s surface first
causes the least damage

Question 9

describe S waves
(2 points)

Answer 9

move slower that P waves
move sideways

Question 10

describe L waves
(3 points)

Answer 10

arrive last
cause the most damage
shake the ground from side to side

Question 11

how are earthquakes measured?

Answer 11

magnitude and intensity

Question 12

how does the moment magnitude scale measure an earthquake?
(4 points)

Answer 12

seismic waves
rock movement
resistance of rocks
the fault surface broken

Question 13

how does the mercalli scale measure an earthquake?

Answer 13

the impact on people, structures and the natural environment

Question 14

what are primary impacts of an earthquake?
(2 points)

Answer 14

building/infrastructure collapse
crustal fracturing

Question 15

what are secondary impacts of an earthquake?
(3 points)

Answer 15

liquefaction
landslide/avalanche
tsunami

Question 16

what is liquefaction?

Answer 16

the surface rock becomes liquid-like causing building collapse

Question 17

what is a landslide/avalanche?

Answer 17

the movement of rock/snow down a slope

Question 18

what is a tsunami?

Answer 18

large waves generated by an earthquake causing coastal flooding

Question 19

when was the san fransisco earthquake?

Answer 19

17th october 1989

Question 20

what was the magnitude of the san fransisco earthquake?

Answer 20

6.9

Question 21

how many deaths were caused by the san fransisco earthquake?

Answer 21

67

Question 22

where was the biggest impact of the san fransisco earthquake and why was it so bad?

Answer 22

marina district
because it was built on landfill and sandy soil which liquified causing the cypress freeway to collapse

Question 23

what are aftershocks?

Answer 23

when the earth readjusts after a major earthquake causing additional damage

Question 24

what did the aftershock cause in the 2011 christchurch earthquake?
(2 points)

Answer 24

more damage to buildings/infrastructure
more deaths than the initial quake

Question 25

what is an intra-plate earthquake?

Answer 25

earthquakes that occur in the middle of a tectonic plate along historic faults

Question 26

how are earthquakes predicted?

Answer 26

they can’t

Question 27

how are earthquakes forecasted?

Answer 27

using historic records

Question 28

what have seismologists forecasted in san fransisco?

Answer 28

67% chance of a major earthquake by 2040