Volcanoes And Earthquakes

Question 1

how do destructive plate margins form a volcano

Answer 1

• the oceanic plate goes under the continental plate as its denser
• oceanic plate moves down the mantle where its melted and destroyed
• a pool of magma forms
• the magma rises through cracks in the crust called vents
• the magma erupts onto the surface forming a volcano

Question 2

how do constructive plate margins form a volcano

Answer 2

• the magma rises up into the gap created by the plates moving away from each other
• forming a volcano

Question 3

what do we call magma that has reached the surface

Answer 3

lava

Question 4

what are hotspots

Answer 4

areas where some volcanoes form over parts of the mantle that are really hot

Question 5

what does a volcano emit out of it when it erupts

Answer 5

• a lot of lava and gases

- some volcanoes can emit lots of ash

Question 6

what can the ash do that volcanoes erupt

Answer 6

• it can cover land
• block out the sun
• or form pyroclastic flows

Question 7

what are pyroclastic flows

Answer 7

super-heated currents of ash, gas and rock

Question 8

what are earthquakes caused by

Answer 8

tension building up between two plate margins

Question 9

how do destructive plate margins cause the potential for earthquakes

Answer 9

• tension builds up when one plate gets stuck

- as its moving down past other into the mantle

Question 10

how do constructive plate margins cause the potential for earthquakes

Answer 10

• tension builds along the cracks within the plate

- as they move away from each other

Question 11

how do conservative margins cause the potential for earthquakes

Answer 11

• tension builds up when plates are grinding past each other in parallel but opposite directions
• and they get stuck

Question 12

how do earthquakes actually occur from all the tension building

Answer 12

• the plates eventually jerk past each other
• sending out shock waves or vibrations
• these vibrations are the actual earthquake

Question 13

how do earthquakes travel

Answer 13

• the shock waves travel from the focus

- near the focus the waves are stronger can cause more damage

Question 14

what is the focus of an earthquake

Answer 14

the point in the earth where the earthquake starts

Question 15

what is the epicentre of an earthquake

Answer 15

the point of the earths surface straight above the focus

Question 16

what are earthquakes measured by and what does that specifically measure

Answer 16

• earthquakes are measured using the moment magnitude scale

- it measures the amount of energy released by an earthquake, called the magnitude

Question 17

what does it mean if the moment magnitude scale is logarithmic

Answer 17

• an increase in the magnitude number means that the power of the earthquake has increased by a scale factor of 10
• so a magnitude 7 earthquake is ten times more powerful than a magnitude 6 earthquake

Question 18

what are the general effects of a magnitude 6 and below earthquake on the moment magnitude scale

Answer 18

• the normally only cause slight damage to buildings

- although they can be worse in very built up ares

Question 19

what are the general effects of a magnitude 7 and above earthquake on the moment magnitude scale

Answer 19

major damage and several deaths