earthquakes and volcanoes

Question 1

name the 4 different plate tectonic movements

Answer 1

constructive
conservative
destructive
colission

Question 2

describe constructive plate margins

Answer 2

2 continental plates move away from eachother which creates a gap in the crust and allows magma to flow through
can cause both earthquakes and volcanoes

Question 3

describe destructive plate margins

Answer 3

oceanic subducts (sinks) under continental due to oceanic being denser-> generate friction -> convection currents created -> create fold mountains and trenches -> can create noth earthquakes and volcanoes

Question 4

describe collision plate margins

Answer 4

plates move towards eachother which creates fold mountains and earthquakes

Question 5

describe conservative plate margins

Answer 5

plates grind past eachother in opposite directions
-cause only earthquakes

Question 6

what 2 plate margins create volcanoes

Answer 6

destructive and constructive

Question 7

how do volcanoes form at distructive margins

Answer 7

1- denser oceanic plate is forced under the contenental plate
2-friction and pressure cause cracks to form
3- margma rises through the cracks and creates a higly explosive volcano

Question 8

what are the 3 different types of volcanoes

Answer 8

-strato (steep and cone shaped)
-volcanic hot spots (abnormally hot,thin crust)
-shield volcano (broad,gentle slopes)

Question 9

how do volcanoes form at constructive boundaries

Answer 9

-convection current causes plates to move apart
-tectonic plates split
-magma explodes due to amount of pressure

Question 10

what is pyroclastic flow

Answer 10

a mix of rock,gas and ash that travel repidly out of a volcano

Question 11

what is ash

Answer 11

mixture of rock minerals and glass particles which can travel thousands of miles by wind

Question 12

what are volcanic bombs made of

Answer 12

dried lava that cools after it leaves a volcano

Question 13

what are lahars

Answer 13

when ash water and ice mix and create a river of mud

Question 14

whats the case study for volcanoes in a developing country

Answer 14

mount st helens

Question 15

what were the causes and effects of mount st helens errupting and when did it happen

Answer 15

-strato volcano erruoted on may 18th 1980
-causes:destructive margin in north american plate, series of small earthquakes
-effects: landslides,pyroclastic flow,57 dead, lake full of debris

Question 16

why do some people chose to live next to a volcano

Answer 16

-fertile soil for agriculture
-attracts tourists which provides job oppourtunities
-naturally hot water-reduced cost

Question 17

how can volcanoes be predicted

Answer 17

increase in gasses
deformed mountains
increase in ground pressure
seismic activity (earthquakes)

Question 18

what are the 4 things can cause earthquakes

Answer 18

-> focus - where the earthquake starts (pressure point)
-> epicenter - directly above focus, where the crust is impacted
-> plate boundary
-> seismic waves

Question 19

what are the 2 scales used to measure eathquakes

Answer 19

-ritcher scale (measures magnitude of earthquakes)
-mercaili scale (seismic activity scale which predicts the effects of the earthquake)

Question 20

when did the hati eathquake happen and for how long

Answer 20

january 12th 2010
35 seconds

Question 21

what were the causes of the hait eathwquake

Answer 21

-epiccenter is captial (port au prince)
-magnitude 7 earthquake
-densley populated country withh poorly structured houses
-corrupt gov

Question 22

what were the impacts of the hati earthquake

Answer 22

-30k dead 1 mill homeless
-buildings collapsed and blocked roads which caused ambulences to arrive late
-ptsd
-damaged sea ports which damaged hatis economy

Question 23

what were the responses to hatis earthquake

Answer 23

-senigal offered land to any hatians
-1.1b collected from charities but only 2 percent released due to corrupt gov
-USA send aid

Question 24

how can we reduce impatcs of earthquakes

Answer 24

-earthquake proof buildings that can easily sway
-triangle strctured buildings
-earthquake drills in schools
-seismographs for preperaition

Question 25

describe earthwuake discribution

Answer 25

-clustured
-close to volcanoes
-uneven disctubution
-near plate boundary

Question 26

explain why earhquakes cause more death than volcanoes (4)

Answer 26

-harder to predict and monitor than volcanoes
-cause more spread of dissease
-starvation
-conjested treats
-lava moves slower so its easier to run away from volcanoes
-earthquakes are more instant
-volcanic erruptions spread while earthquakes usually hit densly populated areas

Question 27

-explain why there was a volcanic erruption in x (descructive) (5)

Answer 27

-destructive
-plate boundaries move closer towards eachother
-convection currents arrise
-oceanic plate subducts
-lies close to plates
-crust melts
-magma rises to surface and breaks crust

Question 28

for a named area explain whats been done to reduce earthquake impact

Answer 28

-sans fransisco california
-seismographs used to monitor readings
-earthquae drills and education at schools
-buildings made of earhquake proof glass and dense and strong foundations
-triangular stuctured buildings
-buildings can sway
-evacuation routes
-1st aid kids and emergency food supplies
-low rise homes so theydont collapse easily
-improved healthcare and doctors