Yr 12 UCAS Tectonic Hazards

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. Secondary effect

Question 13

what are landslides

Answer 13

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

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, Primary Hazard

Question 15

what is tephra

Answer 15

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

Question 16

what are lava flows

Answer 16

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

Question 17

what are volcanic gases

Answer 17

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

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, secondary effect

Question 19

what is jokulhaup

Answer 19

heat of volcano melts snow and ice and causes flooding, secondary effect

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

what is continental drift

Answer 23

there was a super continent called Pangea that became separated, evidence was that Africa and South America looked like a jigsaw, Scotland and Canada have matching rock sequences, Fossils in India and Australia matched

Question 24

what is seafloor spreading

Answer 24

by studying the age of rocks on either side of the Mid-Atlantic Ridge Harry Hess realised that the Earth’s polarity swaps every 400,000 years (Palaeomagnetism)

Question 25

how is a tsunami formed

Answer 25

from the displacement of large quantities of water, created by an underwater earthquake, sub-marine volcano erupting or a landslide

Question 26

what is the pressure and release model

Answer 26

a disaster is the intersection of two processes, on one side its the process generating vulnerability and then the natural hazard event on the other

Question 27

what are the three earthquake measures

Answer 27

Richter Scale, Mercalli Scale, Moment Magnitude Scale

Question 28

what is the Richter Scale

Answer 28

measure of the amplitude of the waves produced, good because its an absolute scale, 0-9

Question 29

what is the Mercalli Scale

Answer 29

measures the experienced impacts of an earthquake, a relative scale because experience different amounts of shaking in different places, based on a series of key responses, such as people waking up or damage to structures

Question 30

what is the moment magnitude scale

Answer 30

modern measure used by seismologists to describe earthquakes in terms of the energy released, based on the ‘seismic movement’ of the earthquake which is calculated from the amount of slip on the fault, the area affected, and an Earth rigidity factor, 0-9

Question 31

what is the volcanic measure

Answer 31

the Volcanic Explosivity Index, a relative measure of the explosivenesss of a volcanic eruption, calculated from the volume of the products, height of the eruption cloud and qualitative observations -0-8

Question 32

what factors contribute to a more vulnerable community

Answer 32

Corruption, Weak political commitment, population density, geographic isolation an accessibility, degree of urbanisation

Question 33

what factors affect the impacts of a tsunami

Answer 33

the duration, the amplitude, the geography of the coastline, if there is a coastal ecosystem buffer, timing of the event, degree of coastal development

Question 34

what are the methods of predicting earthquakes

Answer 34

seismometer, animal Behaviour, Magnitude/Frequency analysis

Question 35

what are the methods of predicting volcanoes

Answer 35

Thermometer, Seismometer, Geometer, Spectrometer

Question 36

what is Park’s model

Answer 36

can be used as a framework to help better understanding the time dimensions of resilience, can be used to help plan and understand risk and resilience, as well as better prepare for future events through modification of the responses to the event

Question 37

what is the Swiss cheese model

Answer 37

suggests that hazard and risk can be reduced by reducing the number of weaknesses and gaps in the response system by modifying the hazard event, modifying vulnerability and resilience, and modifying the loss

Question 38

how can you modify the hazard event

Answer 38

through micro protection techniques such as strengthening individual buildings and structures against hazardous stress, macro protection techniques such as large protective measures designed to protect whole communities

Question 39

how can you protect against an earthquake

Answer 39

strengthening public buildings and facilities, especially those expected to remain operational during a disaster such as hospitals and police stations. Also strengthening schools and factories so that people can shelter in them, and improving the planning frameworks for private houses

Question 40

how can we protect against tsunamis

Answer 40

tsunami walls that work for a given amplitude or threshold of wave, replanting of coasts to use as buffer zones

Question 41

how can you defend against volcanoes

Answer 41

by diverting or shilling the lava flows, land use zoning, GPS and satellite monitoring equipment

Question 42

what is the ability to predict a hazard

Answer 42

the ability to accurately identify when and where the hazard will take place

Question 43

what is the ability to forecast a hazard

Answer 43

the ability to predict what type of the hazard will take place where