tectonic hazards test

Question 1

where are most earthquakes and volcanoes found

Answer 1

along plate boundaries, 70% of earthquakes found in the Ring of Fire in the Pacific ocean

Question 2

what is a divergent plate boundary

Answer 2

when two plates move away from each other, 2 continental magma rises to fill the gap creating a rift valley, two oceanic plates it forms a submarine volcano

Question 3

what is a convergent plate boundary

Answer 3

when two plates move towards each other, when two oceanic the denser plate subducts, when oceanic and continental the oceanic subducts. causes earthquakes due to friction, two continental plates it forms fold mountains

Question 4

what is a Conservative plate boundary

Answer 4

when two plates slide past each other, sinistral ( left) or dextral (right), causes shallow earthquakes

Question 5

what is a hotspot

Answer 5

a volcano created in the middle of the plate, caused by a mantle plume which melts the oceanic crust and forms a submarine volcano which grows into an island arc as convection currents cause the plates to move which forms new volcanos e.g Haiwaiian Ridge

Question 6

what are the three theories of plate tectonics

Answer 6

layers of earth, continental drift, seafloor spreading

Question 7

what are the four layers of the earth

Answer 7

crust, mantle, outer core, inner core

Question 8

what is the Benioff zone

Answer 8

an area of seismicity corresponding with a slab being thrust down into the subduction zone

Question 9

what are p waves

Answer 9

vibrations caused by compressions

Question 10

what are s waves

Answer 10

vibrate at right angles to direction of travel and can’t pass through liquids

Question 11

what are love waves

Answer 11

surface waves which can cause large amounts of damage

Question 12

what is liquefaction

Answer 12

cause buildings to settle, tilt and collapse, lateral spreading causes damage to roads and bridges.

Question 13

what are landslides

Answer 13

occur when slopes weaken and fail, in Kashmir earthquake 1/3 of all deaths due to landslides

Question 14

what is pyroclastic flow

Answer 14

mixture of dense hot rock, lava, Ash and gases that are ejected, 700 degrees and 100km/h

Question 15

what is tephra

Answer 15

pieces of rock and Ash that blast into the air during eruptions

Question 16

what are lava flows

Answer 16

streams of lava that are 1170 degrees and take years to cool completely but are slow

Question 17

what are volcanic gases

Answer 17

water vapour, CO2, sulphur dioxide and can be potentially hazardous

Question 18

what are lahars

Answer 18

masses of rock mud and water that travel quickly down the flanks of a volcano, 10m/s, when eruption melts ice and snow

Question 19

what is jokulhaup

Answer 19

heat of volcano melts snow and ice and causes flooding

Question 20

what is a hazard

Answer 20

a perceived natural event that has the potential to threaten both life and property

Question 21

what is a disaster

Answer 21

a serious disruption of the functioning of a community, which exceeds the ability of the affected community to cope using its own resources

Question 22

what is the risk equation.

Answer 22

hazard x exposure x (vulnerability/ manageability)

Question 23

when was the Icelandic eruption and how many people had to evacuate due to flood

Answer 23

20th March 2010, 700 people