hazardous earth

Question 1

what are the tree primary concentric layers to the earth?

Answer 1

-core
-mantel
-crust

Question 2

how are the core and mantel seprated?

Answer 2

sharp boundry at 2900km
also called moho

Question 3

what are the two layers of the upper mantel?

Answer 3

100km-300km down = asthenosphere, this layer is semi molten or viscous

above this is the lithospshere = a ridgid layer samwhiched between the crust and the asthensosphere

Question 4

thickness of crust

Answer 4

mean = 35km

Question 5

density of crust

Answer 5

contiental - 2.6-2.7
oceanic - 3.0

Question 6

minrel composition of crust

Answer 6

granitic
silicone
aluiminium

Question 7

thickness of mantel

Answer 7

to a depth of 2900km

Question 8

desnity of mantel

Answer 8

moho=3.3
core=5.6

Question 9

minrel composition of mantel

Answer 9

rich in magnesium and iron

Question 10

what do the lithosphere and crust make up?

Answer 10

congenital and oceanic plates

Question 11

where do convection currents exits?

Answer 11

ashensosphere

Question 12

what causes the convection currents?

Answer 12

caused by the vast amount of heat generated deep in the mantel as a result of the semi molten asthensophere flows carrying with it the solid lithoshpere and crust

Question 13

contiental drift theory orgin?

Answer 13

durin the 18th centrey maps of the world multiplied and became more accurate and the shapes of the continents and their relationship to each other attracted intrest

Question 14

first writer on the fit between northeast south America and the west coast of Africa?

Answer 14

Alexander Von Humbodt

Question 15

who came up with the contiental drift theory?

Answer 15

Alfred Wenger 1912

Question 16

key ideas of the contiental dirft theory?

Answer 16

-prosed that in the carboniferous period, 250 million years ago a large continent Pangea exited and this slowly broke apart into two large land masses

Question 17

Alfred Wenger geological evidence?

Answer 17

-fit of continents such as the south America and south Africa on either side of the Atlantic

-mountine chains of rock sequenses on either side of the ocean show great simularity e.g northeast Canada and northen Scottland

-glacial evidnece is present at rocks on continents that are now located close to the equator

-glaciers leave deposit behind such as till, which is the sediment depoisted under a glacier as it retrets

Question 18

sucsess level of mitgation will depend upton

Answer 18

record of past events
-time gap since past event (gap theory)
-nature of tectonic activity
- attutuide
-resilliance of people effected

Question 19

mitgation against the event

Answer 19

land zoning
tusnami defense - sea walls and water breakwaters
lava diversion
mitgation against vunrebility
community prepration and eductaion
aseismic buildings
adaptation
mitgation against loss
long term aid
insurance

Question 20

land zoning

Answer 20

relocation and avoiding building on certain areas
- low cost, relocation
-prevents economic development
-requires struct reenfourcement

Question 21

tusnami defense

Answer 21

sea walls and water breakwaters
-reduce damage, sense of security
-if over topped it can cause damage
-expensive and unsightly

Question 22

lava diversion

Answer 22

builds channels and cools lava with water
-divert away from important buildings, cheap compared to damage,
-only works for basaltic lava
-not feasable for most expolsive volcanos

Question 23

mitgation against vunrebility

Answer 23

high tech montering
can be accurate and save lives
-costly, cry wolf syndrom
-property is still damages

Question 24

community prepration and eductaion

Answer 24

-low cost and orgnised by NGO’S, saves lives localy
-property still damaged and hard to implemnt in rural areas

Question 25

aseismic buildings

Answer 25

cross bracing, counter weights, deep foundations -protect ppl and property, financuial possible in developed world and developing world can copy infustructure -high cost especially for tall buildings, diffcclt to implemnt on tall buildings -perasonal houses (ppl cant afford)

Question 26

adaptation

Answer 26

moving out dangerous areas and relocating -saves lives and property -hard in densely populated areas -disrupts peoples lives

Question 27

mitgation against loss

Answer 27

emergancy aid, search and rescuse, emergancy food, water and shealter. -reduce death toll, keeps people alive untill the goverment come -costly in hard to reach areas EDC'S AND LID'C are poorly equipt

Question 28

long term aid

Answer 28

reconstruction, improvement to resilience -imcorprates land use planning established better construction methords -high cost

Question 29

insurace

Answer 29

compensation given -allows econmey to recover -doesnt save lives few people in EDC'S AND LICD'S CAN AFFORD

Question 30

incraesed risk

Answer 30

as the global population increases more poeple live in towns and cities greater number of people and propties are at risk from earthquakes and volcanos