Plate tectonics

Question 1

LIC Earthquake

Answer 1

Port-au-Prince, Haiti
2010
7mm a year
magnitude 7
shallow focus of 13km
primary- 250000 dead, flattened in less than 60s, buildings collapsed,liquefaction, 4000 prison inmates escaped
secondary-1.5 homeless, 6.1 magnitude aftershocks, crippled government, local food prices rose
response- UN aid as food and shelter, US took over military, 690000 in 600 camps, cholera outbreak, 3000 temporary tent schools, economy slowly rebuilt, farming for sufficiency

Question 2

HIC Earthquake

Answer 2

L’Aquila, Italy
2009
6.3 magnitude
seismically active, 3cm a year
complex fault system- African push up on Eurasion
population=70000
Primary- 300 dead, 15000 injured, buildings collapsed, burst water pipes
Secondary- 34000 homeless, living in tents, loss of heritage, increased looting and crime
Responses- criticised for failing to meet architectural needs (buildings that were meant to withstand EQ were poorly built), official government enquiry, declaration of state of emergency, camps quickly set up. fully rebuilt within 2 years. cost=$15billion

Question 3

Tsunami- Indonesia

Answer 3

Indian Ocean
2004
1am at night- lots asleep
250km from coast
9.3 magnitude- 2nd biggest
Causes- fault slip, release of stress, Indian plate moved down my 15m, ocean floor punched upwards several meters, 8 aftershocks
Primary- 290000 dead, 1mil injured, whole coastal villages destroyed, vegetation/top soil lost, infrastructure lost- no access to some places, 14 countries affected
Secondary- widespread homelessness, loss of industry (fishing and tourism), 44% lost livelihoods, water supplies contaminated by salt. $9.9billion repair costs

Question 4

Geothermal power

Answer 4

Kenya
3 plants in Great African Rift valley
1st African country to do so
11.2% of total energy needs
Advantages- renewable, sustainable, high efficiency, cheap for residents, no fossil fuels
Disadvantages- locations may change, high initial investment costs, large amount of land, unpleasant smell

Question 5

Geothermal Tourism

Answer 5

Iceland
5 geothermal power plants on top of Atlantic Ridge
1/3 all country’s electricity
90% of all heating needs (water/buildings)
covered with lava and geothermal fields
Hveragersi Geothermal Park:
South Iceland
natural clay foot baths, hot springs
restaurants only use geothermal energy to cook with
hiking and riding trails with guides
first shopping centre opened in 2004

Question 6

Hotspot

Answer 6

Hawaiian Islands
700million years old
32000km from oldest to youngest- 9 islands
a plume, as crust moves, new volcanic islands form
Hawaii is youngest- only active one
move 10cm a year

Question 7

Supervolcano

Answer 7

Yellowstone, Wyoming
chain of extinct volcanoes and calderas through California and Idaho
erupted 640000years ago
48km by 72km
half of world's geothermal features
Old Faithful- every 45-90 minutes
If erupted:
1000cubic meters of magma
giant caldera
ash would change global climate

Question 8

LIC Volcano

Answer 8

Nyiragongo, DRC
2002
associated with Albertine Rift
20km north of Goma and Lake Kivu
Boarder Rwanda
Unexpected eruption- but warnings of lava meant people could flee
fissure 13km lond, 2m deep
lava flow in direction of town
Primary- 1/3 Goma destroyed, water and power supplies destroyed, medical facilities lost, airports shut, 147 dead
Secondary- lava polluted lake, lack of food and shelter, diseases, release of toxic gas from lake, 200000 homeless crossed into Rwanda
Responses- red alert, evacuation, aid from UN 2 days after, water supplied in tankers for months

Question 9

HIC Volcano

Answer 9

Mount Etna, Sicily
2011
east coast
one long eruption since 2011
strongest in 1669
composite volcano- tall steep sides, layers of ash and lava, explosive viscous lava
Causes- subduction of African under Eurasian, destructive margin, Europe’s highest and most active volcano, 500000years old, 25% of population lives on sides

Question 10

Destructive

Oceanic-Continental

Answer 10

Peru-Chile Trench
Nazca plate subducts under South American
Oceanic Continental
deep focus earthquake in benioff zone
convection currents in asthenophere

Question 11

Destructive

Oceanic-Oceanic

Answer 11

Marianas Trench
Philippine Plate and Pacific Plate
Depression in ocean floor
More dense subducts under less dense

max depth= 10000m

Question 12

Destructive

Continental-Continental

Answer 12

Himalayas
continental plates are less dense than asthenosphere below
sediment crumples up

Eurasian and Indian plates
2400km long
40-50 million years ago
growing 67cm a year

Question 13

Conservative

Answer 13

San Francisco earthquake
Pacific and North American
plates slide past each other- friction build up

Great San Fransisco earthquake 1906, 7.9 magnitude, 700 dead
Los Angeles earthquake 1994, 6.6 magnitude, 57 dead

Question 14

Constructive (valley)

Answer 14

Great African Rift Valley
plumes of magma rising from asthensphere
magma heated overlying plates causing them to expand
as plate heated, it’s stretched and fractures along fault line
Horsts and Grabens
Interconnecting valleys run through Kenya, Uganda, Tanzania and Ethiopia
Eventually lowland below sea level

Question 15

Constructive (Island)

Answer 15

Surtsey
1963
Eurasian and North American plates (both oceanic)
Submarine erosion caused sea level to boil- 3.5 years
Magma rose, lava cools to form new crust

3km^2, 154m high, 90% under sea

Question 16

Tsunami- Japan

Answer 16

Japanese Quake
2011
magnitude 9
Pacific plate subducted under North American plate
Primary effects- 16000 deaths, 26000 injured, 46000 buildings destroyed
Secondary effects- ruptured dam led to more flooding, power plant in state of emergency (a nuclear warning zone- year after still), many areas left deserted