HAZARDS & tectonic plates Flashcards Preview

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Flashcards in HAZARDS & tectonic plates Deck (39)
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1
Q

define hazard

A

harmful elements of the physical environment caused by extraneous forces.

2
Q

define natural phenomenon

A

physical event that doesn’t affect humans

eg) cyclone yvette

3
Q

define natural disaster

A

physical event that causes large amounts of property damage and over 10 deaths.

4
Q

define natural hazard

A

natural phenomenon that occurs in a populated area creating a hazard.
(Eyjafajallajokull 2010)

5
Q

classifications of hazards

A

geomorphological, atmospheric, biological, tectonic

BUT the categories can become blurred.

6
Q

Hazard Perception… eg?

A

way someone interprets/ understands a hazard

fatalism, adaption, domination, fear

7
Q

fatalism

A

nothing can be done = acceptance (god?)

8
Q

adaption

A

action taken to reduce vulnerability

9
Q

domination

A

hazards are predictable and can be understood with science

10
Q

fear

A

ppl flee to unaffected regions

11
Q

3 ways to respond to hazards

A

prevention, prediction and AID

12
Q

What is the park model?

A

show changing quality of life through different phases of disaster ( 1-5) as humans respond.

13
Q

stages of the park model (NHRRR)

A

1) NORMALITY = preparation/ modification
2) HAZARD = declining quality of life & ppl protect
3) RELIEF(hrs and days) = search, care & rescue
4) REHABILITATION(days-wks) = improvements to modify loss - water, food, shelter
5) RECONSTRUCTION(wks-yrs)= reduce vulnerability and restore normality / improve.

14
Q

Hazard Management cycle (four stages) RRMP

A
RESPONSE = minimise hazard
RECOVERY = return to normality
MITIGATION = minimise effects of disaster
PREPAREDNESS = planning effective response.
15
Q

Problem with Hazard Management Cycle

A

steps do not occur chronologically = overlap and severity and development affect duration.

16
Q

Earths age

A

4.6 billion yrs old

17
Q

describe the inner core

A

solid and made from nickel and iron

6000*C

18
Q

describe the outer core

A

liquid and made from nickel and iron

4-5000

19
Q

describe the Mantle

A

the thickest section

made of silicate of iron, magnesium, sulphides and oxides.

20
Q

difference between the asthenosphere and the lithosphere

A
Asthenosphere = soft, plastic rock that makes convection currents 
Lithosphere = solid upper part of mantle and crust = tectonic movement
21
Q

describe the continental crust

A

thicker, older, less dense than oceanic

22
Q

describe oceanic crust

A

thiner, younger and denser than continental

23
Q

evidence of continental drift (7)

A

jigsaw fit, fossil correlation, rock and mountain correlation, paleoclimate data, see floor spreading, paleomagnestism

24
Q

example of paleoclimate data

A

glacial striation

25
Q

rock composition of oceanic crust

A

basalt, gabbro and silma

26
Q

rock composition of continental crust

A

granite and sial

27
Q

what is paleoclimate data?

A

study of how characteristics of land match with the climate eg) glacial striation sign of moving glaciers = must have one been in cold environment

28
Q

what are some signs that land must have been in a different climate?

A

glacial striations and coal deposits.

29
Q

what processes finally proved Wegener’s theory of continental drift

A

sea floor spreading and paleomagnetism

30
Q

how often does the earths magnetic field swap?

A

every 400,000 yrs … or so.

31
Q

What is ridge push? (gravitational sliding)

A

an alternative hypothesis for the mechanism of plate movement.
- magma rises to surface at plate ridge
- surrounding rock becomes very hot and expands
- expansion elevates the sea floor = slopes either side
- rock formed cools and condenses = gravity pulls it inwards = moved apart down slope away from ridge.
(sea floor spreading pushes plates away from ridge)

32
Q

what is slab pull?

A

a more dominant theory for plate movement

  • subducted oceanic plate is denser
  • the sinking plate pulls the rest of the plate down further with its weight.
33
Q

geographical features found at constructive plate boundaries

A

mid ocean ridge - chain of submarine volcanoes
shield volcanoes
rift valleys - fractures form between two plates - new and sinks due to movement = steep sided valley.

34
Q

geographical features at destructive plate boundaries

A
ocean trenches - subduction zone between plates
fold mountains - andes
island arcs - chain of volcanic islands 
volcanoes
earthquakes
35
Q

geographical features at collision plate boundaries

A

fold mountains - continental plates collide - neither subducted = crust buckles and crumples

36
Q

geographical features at conservative plate boundaries

A

plates do not pass smoothly = friction locks plates and courses earthquakes when pressure is released = changing structure of land.

37
Q

magma plumes

A

vertical column of magma that rises up from the earths causing a volcano to form away from a plate margin.

38
Q

geographical features of magma plumes

A

supervolcano

island arc - plates move over hotspot and weaknesses in the rock allow magma to escape onto the surface.

39
Q

benioff zone

A

and inclined zone in which lots of deep earthquakes can occur as subducted rock is melted and destroyed.
found beneath destructive boundaries where oceanic plate is being subducted.