PMT - hazards caused by seismic events

Question 1

what are some of the hazards that can be caused by seismic hazards?

Answer 1

shockwaves
aftershocks
tsunamis
liquefaction
landslides and avalanches

Question 2

what is shockwaves (seismic waves)?

Answer 2

two plates move side by side and friction builds up

pressure increases and is stored as potential energy and builds up

the pressure becomes too much and its transferred into kinetic energy which is released and vibrates throughout the ground

Question 3

how does a tsunami form?

Answer 3

an oceanic crust is jolted during an earthquake and the water above the plate is displaced

water travels fast with a low amplitude

the closer to the coast the sea level decreases

the friction between the sea bed and the waves increases

causing the waves to gain height

Question 4

example of where a tsunami took place

Answer 4

japan

initial earthquake was 9 on richter scale

2011

around 19,500 deaths

focus was around 30km below the floor of the western pacific ocean

Question 5

what are aftershocks and how long can they last for?

Answer 5

seismic waves shaking as under the ground crust is readjusting

days weeks months years

Question 6

what is liquefaction?

Answer 6

when violently shaken, soils with a high water content lose their mechanical strength and behave like a fluid

Question 7

example of when liquefaction took place

Answer 7

new zealand, christchurch

2011

10s of thounsands properties damaged

6.3 magnitude richter scale

Question 8

what happens during an avalanche or landslide?

Answer 8

movement in soil or snow will cause it to become unstable

Question 9

example of an avalanche

Answer 9

nepal

2015

richter scale 7.9

19 killed by avalanche at mount everests camp

around 9,000 killed

(avalanches) blocking roads hampering the relief effort