hazards -forms of seismic hazards (shockwaves)

Question 1

what are the forms of seismic hazards?

Answer 1

.shockwaves
.tsunamis
.liquefaction
.landslides

Question 2

how do shockwaves occur?

Answer 2

.friction along plate margins builds up in the lithosphere and when the pressure is finally released, they fracture along cracks called faults, sending a series of seismic shockwaves to the surface

Question 3

what does the nature of a seismic hazard depend on?

Answer 3

.depth of focus
.width of seismic activity
.frequency of earthquakes
.magnitude of earthquakes

Question 4

what is the breaking point of the pressure called?

Answer 4

.the focus of the earthquake

Question 5

what is the epicentre of the earthquake?

Answer 5

.the point on the surface directly above the focus, it usually experiences the most intense ground shaking

Question 6

how many types of depths of focus are there?

Answer 6

3

Question 7

what are the 3 types of depths of focus?

Answer 7

.shallow focus earthquakes -0-70km deep and tend to cause the greatest damage -account for
75% of all earthquake energy released
.intermediate focus occur between 70-300km
.deep focus earthquakes occur at depths of 300-700km

Question 8

what are the factors that affect the nature of a seismic hazard at a constructive plate margin?

Answer 8

.shallow focus earthquakes <60km - as a result of tensional forces in the crust -often small in size and occur at mid-ocean ridges so pose little risk to people
.narrow zone width
.regular frequency
.low magnitude

Question 9

what type of focus depth is there at a conservative plate margin?

Answer 9

.shallow focus earthquakes up to 20km
.narrow zone width
.infrequent
.high magnitude

Question 10

what type of focus depth is there at a destructive collision plate margin?

Answer 10

.mainly shallow
.wide zone width
.infrequent
.high magnitude

Question 11

what type of focus depth is there at a destructive subduction plate margin?

Answer 11

.range from intermediate to deep 70-700km
.wide zone width
.infrequent
.high magnitude

Question 12

what are the 2 types of shockwaves?

Answer 12

.body waves
.surface waves

Question 13

what are body waves?

Answer 13

.shockwaves that travel through the earth

Question 14

what are body waves categorised into?

Answer 14

.primary (P) waves
.secondary (S) waves

Question 15

what are P waves?

Answer 15

.waves that travel through both liquids and solids and are the fastest waves, reaching the surface first
.they are compressional waves
.travel through the curst, mantle and the core

Question 16

what are S waves?

Answer 16

.waves that travel through the earth but cannot travel through solids such as the core
.half as fast as P waves
.transverse waves (they shake the ground at right angles to the direction of the wave)

Question 17

what are surface waves?

Answer 17

.waves that travel along the earths surface

Question 18

what can surface waves be categorised as?

Answer 18

.love (L) waves
.rayleigh (R) waves

Question 19

what are love (L) waves?

Answer 19

.slowest but most destructive
.shake the ground from side to side

Question 20

what are rayleigh (R) waves?

Answer 20

.they travel out from the epicentre near the surface
.move in a rolling motion
.they can break up surface