tectonic hazards

Question 1

which is denser - an oceanic plate or a continental plate?

Answer 1

the oceanic plates are denser

Question 2

what causes the tectonic plates to move?

Answer 2

convection currents

Question 3

which way are the plates moving at a constructive plate boundary?

Answer 3

they move apart - diverge

Question 4

what is created at a constructive plate boundary?

Answer 4

volcanoes becuase magma forces its way through the gap

Question 5

which way are the plates moving in a conservative plate margin?

Answer 5

they are sliding past each other

Question 6

what is caused at a conservative plate margin and why?

Answer 6

earthquakes becuase the rocks have jagged edges so they snag when the two plates are sliding past each other - this causes friction and tension to build up

Question 7

how are the plates moving in destructive plate boundaries?

Answer 7

the oceanic plate slides beneath the continental plate

Question 8

what can be formed at a destuctive plate margin?

Answer 8

a volcano becuase the magma rises to the surface in cracks in the continental plate - very explosive volcanos

Question 9

what are the primary effects of a volcanic eruption?

Answer 9

-damaged buildings
-deaths/suffocation
-crop and livestock deaths

Question 10

what are the secondary effects of a volcanic eruption?

Answer 10

-loss of forests or farmland
-infratructure damage
-increased soil fertility
-economic damage
-volcanic winter (can cause famine as crops wont ripen)
-flooding and tsunamis (result of tectonic activity)
-lahars (mudflows)

Question 11

what are some immidiate responses to volcanic eruptions?

Answer 11

-evacuation
-aid from NGOs and foreign govs
-temporary infrastucure created for evacuated people

Question 12

what are some long term responses to volcanic eruptions?

Answer 12

-relocation
-government efforts to rebuild the local economy (eg tax breaks)
-rebuild infrastructure

Question 13

at what boundaries can earthquakes happen?

Answer 13

all three!

Question 14

define an earthquake

Answer 14

sudden or violent movements in the earths crust

Question 15

what is a seismic wave?

Answer 15

the shock waves released from the focus

the most damage will be done at the places where the shock waves are strongest

Question 16

what is the epicentre?

Answer 16

the point on the earths crust that is directly above the centre of the earthquake

Question 17

what is the focus in an earthquake?

Answer 17

where the pressure is released underground and where the energy radiates out from

place with the strongest waves that cause the most destruction

Question 18

what scale is used to measure earthqaukes?

Answer 18

the moment magnitude scale measures how much energy the quake releases

Question 19

what are some immidiate responses to earthquakes?

Answer 19

-aid from charities
-temporary infrasructure like energy, electrisity, phone lines
-temporary housing
-rescue operations for trapped people and bodies

Question 20

what are some longterm responses to earthquakes?

Answer 20

-improve preperation
-improve the local economy (gov. grants or encourage tourism)
-rebuild buildings and infrastructure

Question 21

give some ways that we can reduce the impact of tectonic hazards

Answer 21

-using seisometers to monitor and detect the movements in the earth
-predicting them by looking at tectonic plate boundaries so we know where they could happen

Question 22

what three signals can indicate a volcanic eruption?

Answer 22

-small earthquakes
-bulges
-gas emission

Question 23

Give some ways that we can reduce the impact of tectonic hazards

Answer 23

-protection like earthquake proof buildings or automatic switches that turn off gas taps (in high income countries)
-protection like light roof materials and bamboo instead of metal support in walls (in low income countries)
-planning for evacuation systems

Question 24

Give some reasons why people would live in a place with tectonic hazards?

Answer 24

-they have family in the area
-the land is fertile due to volcanic ash (good farming)
-good government that has plans for evacuation
-jobs