The Restless Earth Flashcards
Primary effects of volcanos?
Volcanic blast - power of which can blow things over Pyroclastic flows Livestock and crops destroyed Buildings destroyed Lava flow Volcanic bomb
What earthquake activity occurs at a constructive plate margin?
Low magnitude earthquakes
Examples of earthquake proof things?
Transamerican Pyramid
intelligence anti earthquake bed
What landforms occur at a constrictive plate margins?
Shield volcanoes
What is a volcanic bomb?
Large boulders and stones are hurled out of the volcano during an eruption
Description of Richter scale?
11th March 2011
9.0 on Richter scale
100km easy of Sendai on Honshu
10m in height
What type of scale is the Richter scale?
Logarithmic
What are lahars or mudflows?
When rain brings spot and ash back to the ground it becomes heavily saturated mudflow when combined with snow and ice
Describe the richer scale?
Used info from seismometer
Record strength of shock waves and movement
Seismogram produces a line graph of waves (seismograph)
Logarithmic
General uses of fold mountains?
Farming
Mining
Tourism
HEP
Why do plates move towards eachother?
Convection currents
How far was L’Aquila’s focus from the surface?
8.8 km
How can spiders help to monitor volcanos?
Spiders (robots) are added to craters to monitor sulphur dioxide concentration which can signify an eruption
How is the Richter scale used to measure earthquakes?
Information collected by seismometers
That record the strength of shock waves and amount of movement through line graphs
This then indicates a number between 0/1 and 10
What happens to tsunamis in deep water?
Travels fast but with a shallow wave height
Describe a conservative plate margin?
Two plates do not directly collide but slide past eachother along a fault
No volcanoes are formed along these plate boundaries but earthquakes do occur
What causes a tsunami?
Rarely a large meteorite
A volcanic eruption
Underwater landslide
Powerful undersea earthquake
MEDC earthquake response?
More money for prediction and government
Planned response
Larger companies involved
Date of hati earthquake?
12th January 2010
Characteristics of a shield volcano?
Flat top Low lying Broad base Gentle sloping sides Little ash Non explosive Frequent eruptions
LEDCS earthquake response?
Poorly constructed buildings
Poor communication links
Spread of disease (due to a lack of clean water)
What were the primary effects of Haiti?
220,000 deaths 300,000 injuries 5 aftershocks 1.3 million people displaced 8 hospitals damaged Port damaged Road blocked
Examples of a conservative plate margin?
Mid Atlantic ridge
North American and Eurasian plate
Features of constructive plate boundaries?
Shield volcanos
Low magnitude earthquakes
Formation of a composite volcano?
Plated move towards eachother due to convection currents in mantle
Oceanic (denser) subducts under continental
Melting occurs due to friction and heat
Pool of magma forms which rises
Pressure released in an eruption
Giving steep sided volcano of lava and ash
National effects of a super volcano eg Yellowstone?
Flights suspended
Livestock die (choke on hot ash)
Road transport difficult
What is the magma like in a super volcano?
Large amounts of silica
Viscous
Cools quicker
Explosive
How can earthquakes be prepared for?
Drills
Activities
Education in school
Seismic risk map
Describe a destructive (collision) plate?
When two plates of similar densities move together
This caused the material between them to buckle and rise up forming fold mountains
Characteristics of shield volcanos?
Gentle slopes Wide base Frequent eruptions Non violent High speed lava flow Less viscous Low lying Little ash Rounded
Effects of Monserat volcanic blast?
Huge pyroclastic flows over 500 degrees : 3 main ones came down ‘Mosquito Gut’
50% of Montserrat is uninhabitable
Infrastructure eg airport and roads destroyed
19 died
Montserrat’s economy was de estates
Explain how volcanos are formed at constructive plate margins?
Convections currents in the mantle cause plates to be pulled apart
A gap is created which is filled with rising magna
This cools to form lava
As the plates shift apart more magma is released from the mangle
This fills the gap and the layers build up to form a volcano under the ocean
How can monitoring volcanos help?
Changed to be identified in advance means evacuation
What is a fault?
A large crack in the earths crust
Effects of a tsunami?
20,000 people killed 6 million without electricity 1 million without water Over 1,000 aftershocks 500 km squared of costal plains inundated Ruptured gas pipes led to fires Explosions occurred at Fukushima Stock marts fell Billions of dollars of damage
HEP in Andes case study?
Steep narrow valleys Suitable for dams Steep relief provided fast flowing water needed to turn turbines Yuncan project El Platinal (2009) Dams the Cañene River
Natural warning for a tsunami?
Sea retreats hundreds of metres leaving hundred of sea bed exposed as wave approaches
Definition of fold mountains?
Mountains formed from the folding of the earths crust
Where rock layers have crumpled into anticlines and syncline a as they have been pushed together
What did Haiti measure on the Richter scale?
7
Features of the mantle?
Molten
1300-5000 degrees
^ just below the crust
Features of the crust?
Outer layer of earth
Thin layer
Solid
6-70 km thick
Think skin of an apple
Why did Haiti happen?
Subduction plate boundary - Atlantic subducts Caribbean
Earthquake occurred due to pressure Sudden release (strike slip)
What would happen in the country of a super volcano erupted?
One in three killed within 1000 I’m
Buildings would collapse due to weight of ash
Ground planes and road transport difficult
Livestock would chocke in ash
Describe the size and shape of a super volcano?
Large eruption
At least 100 cubic km of metres is erupted
Around flat areas
Tens to be sunken surrounding higher land
How do earthquakes form at destructive plate margins?
Oceanic moves towards continental
Oceanic subducts under continental as it is more sense
This exerts great pressure on the crust
This builds up over time
Release of this pressure caused the plates to shift
EARTHQUAKE
How can earthquakes help to monitor volcanos?
Earthquakes monitored as this can trigger volcanic eruption
If they are stronger or more frequent
Why do the largest earthquakes not always cause the most deaths?
Population density may be low so few people present in the danger area
Describe a constructive plate boundary?
Convection currents in the earths mantle force the plates at this boundary apart
New oceanic crust is created which can emerge as volcanic islands
How can earthquakes be predicted?
Historical data
85% occur at plate boundaries
Seismic mapping (tremors)
CANT PREDICT WHEN
Secondary effects of Montserrat?
Fires destroyed buildings infrastructure destroyed led to no trade
Loss of tourism
Volcanic ash improved solid fertility
Population decline of 8,500 people
Secondary effects of Haiti?
Landslides 2 million without food and water Looting - collapse of police force $14 billion in economic damage Disease in tented camps Power cuts 100,000 people had diahorria
What happens at destructive subduction boundaries?
Fold mountains
Higher magnitude earthquakes
Ocean trench
Volcanos
Primary effects of Haiti?
220,000 killed 300,000 injured 1.3 million people displaced 100,000 houses destroyed 8 hospitals damaged 200,000 damaged houses
How many cm do the plates move every year?
3cm
Features of the outer core?
Liquid
Mostly iron
Why did Haiti happen?
Subduction plate boundary - Atlantic subducts Caribbean
Earthquake occurred due to pressure Sudden release (strike slip)
Primary effects of Montserrat?
Plymouth (cc) buried 19 killed and 7 injured 50% of Montserrat uninhabitable Loss of houses farms schools hospitals airport vegetation and farmland 20 villages destroyed
Why don’t largest earthquakes cause the most deaths?
Low population density
Few people in danger area
What is the earths focus?
Within the earths crust where the earthquake begins
On the Richter scale, what does an increase of 1 represent?
A 10 fold increase
How can earthquakes be protected?
Fire resistant building materials
Open areas for evacuation
Computer controlled weights on root to reduce movement
Rubber shock absorbers to absorb tremors
Bird cage interlocking steel frame
Found stings sunk in bedrock avoiding clay
Primary effects of Montserrat?
Plymouth (cc) buried 19 killed and 7 injured 50% of Montserrat uninhabitable Loss of houses farms schools hospitals airport vegetation and farmland 20 villages destroyed
Features of the inner core?
Solid (as under the most pressure)
An be as hot as 5500 degrees
Solid iron
Before the eruption in Montserrat how many people lived there?
12,000
Now
5,000
How do you measure volcanos? What does it measure?
Volcanic explosivety index
Measures 8 = top of the scale
Farming case study Andes?
Milk and wool for clothes and rugs Cash crops eg cotton Llamas used as pack animals Females used for meat Growing of subsistence crops eh potatoes on terraces
Give two differences between the continental crust and oceanic crust?
Continental crust is less less dense than oceanic
Continental is older than oceanic
Continental is thicker
Continental can be destroyed
Why did the volcano at Montserrat form?
Subduction of the Atlantic plate under the Caribbean plate
Describe a destructive plate boundary (subduction zone)?
Where an oceanic plate meets a continental plate
The oceanic plate subducts under a continental plate because it’s denser
As the plate subducts it starts to melt due to friction caused by movements between the plates and the heat
The melted plate is now hot liquid rock
The Magna ride through gaps in the continental plate
It reaches the surface and forms a volcano
Describe pyroclastic flow
ash is ejected into air loses ability to be suspended so falls back to earth. Hit ash and gas runs down side of mountain at great speed.
Features of the oceanic crust?
Thinner Younger Destroyed and re made Sinks More dense
Why don’t the largest earthquakes cause the most deaths?
Low populations density
Few people in danger area
Poor areas so buildings kill people
Responses to L’Aquila earthquake?
161 tented settlements for homeless
Red Cross set up field kitchens serving 10,000 per day
Mobile companies provided free phones
Mobile offices sent to homeless camps so people could access money + pensions
30,000 grants worth 2.4 billion euros
Investigation into buildings
All tax payments stopped by government
100% government funded reconstruction
Effects of L’Aquila earthquake?
295 deaths 2,000 injured Bridge near Fossa collapsed Streets impassable Loss of medieval buildings Dormitory collapsed
Fires in collapsed buildings
$2.5 billion economic damages
34,000 homeless
Broken water pipe near Paganica caused a landslide
International effects of a super volcano eruption eg Yellowstone?
Temperatures fall by 10-15 degrees making it difficult to grow good
U.K. Revived ash five days later
Parts of Europe covered in snow for 3 years meaning no food
40% of population starve to death
Failed monsoon
Huge avalanches
What caused Japan tsunami?
Pacific plate subducts under North American
Earths crust flicked up between 5-10n
Formation of a shield volcano?
Convection currents force played apart Magma rides up from magna chamber Magna plugs the gap, Some is forced along vent and erupts at the surface Magna reached the surface as lava Erupts and cools to add new layers
Explain the formation of fold mountains?
Rivers erode material and transport it to sea
deposited on the sea floor
Layers build up and are compressed
Forming sedimentary rock
At destructive (collision) plates move together and rock crumpled
Can also be formed at subduction where continental crumpled as it meets oceanic crust
What landforms form at a destructive plate boundary (subduction zone)
Fold mountains
Ocean trench eg Mariana
Volcanoes
Mining case study Andes?
Tin,nickel, silver, gold
Yanacocha gold mine in Peru is largest in the world
Led to expansion of Cajamarca
From 3,000 to 240,000 inhabitants
Why did Montserrat occur?
Destructive (subduction) plate boundary
Atlantic subducts RED under Caribbean
Was dormant for 200 years
What happens to tsunamis in shallow water?
It slows causing the wave to rise up or increase in size
What is the epicentre?
The point on the eather surface directly above it
Describe the mercalli scale?
Effects of earthquake
1-12
Ask eyewitnesses for observations using photos or words
Short term responses to Montserrat?
April 1996 Plymouth was evacuated
Support units to search and rescue survivors
U.K. Provided £17 million in emergency aid
Temporary infrastructure built
Long term responses to Montserrat?
People returned
MontserrT observatory set up in 1996
New harbour at ‘little bay’ new airport and new roads
Risk map created
South of island still of limits
£200 million to restore electricity and water and build infrastructure from Britann
What are the features of a destructive (collision) plate?
Fold mountains
Higher magnitude earthquakes
Secondary effects of earthquakes?
Fires - usually from ruptured gas lines
Tsunamis
Disease - unsanitary conditions leads to fast spread
Landslides - huge amounts of material move quickly
Describe the size and shape of a super volcano?
Very large scale, colossal eruption (at least 1000 cubic I’m of material)
Tend to be sunken surrounded by area of higher land, flat land
What date did L’Aquila happen?
6th April 2009
Effects of a tsunami?
20,000 people killed 6 million without electricity 1 million without water Over 1,000 aftershocks 500 km squared of costal plains inundated Ruptured gas pipes led to fires Explosions occurred at Fukushima Stock marts fell Billions of dollars of damage
Local impacts of super volcano eruption eg Yellowstone?
Large ash cloud rising of 40-50jm in atmosphere
10,000 square km of land destroyed
15 cm thick ash covering buildings within 10,000 km which collapse under the weight
Deaths (one in three killed within 1000km of eruption)
Andes case study?
7000 km
West coast of South America
Explain the formation of fold mountains?
Rivers erode material and transport it to sea
deposited on the sea floor
Layers build up and are compressed
Forming sedimentary rock
At destructive (collision) plates move together and rock crumpled
Can also be formed at subduction where continental crumpled as it meets oceanic crust
Explain how volcanoes form at constructive plate margins?
Plates pull apart due to convection currents in the mantle
A gap is created which is plugged by rising magma
This cools to form lava
As the plates shift apart more magma is released from the mantle to fill the gap
The layers build up to form a volcano under the ocean
What is the difference between the focus and the epicentre of an earthquake?
Focus is within the earths crust
Where the earthquake begins
Where’s the epicentre is the point directly above the focus
Describe how volcanos are monitored?
Earthquakes occurring more frequently or strongly are a sign that an eruption is likely to occur - warning and time to prepare
Tilt meters record even a slight changes in the shape of the land and spiders monitor gases - the concentration of sulphur dioxide increases before an eruption
Allows time to stock up on supplies and allow time for evacuation
Date of Montserrat’s eruption?
June 1997
Tourism in the Andes case study?
Scenery of high peaks, glaciers, lakes and valleys Inca trail (45km) + Macchu Picchu Weaving clothes and scarves South American food Markets and crafts
Where do earthquakes occur?
Along faults
What is an ocean trench?
Long narrow steep sided depression in the earths
Features of conservative plate boundaries?
Higher magnitude earthquakes are common
What is a tsunami?
A series of large waves generated by the movement on the ocean floor
Secondary effects of volcanic eruptions?
Lahars and mudflows Insurance claims Climate change Homelessness Buisnesses forced to close Unemployment Flood and water supply distrusted
Farming case study Andes?
Milk and wool for clothes and rugs Cash crops eg cotton Llamas used as pack animals Females used for meat Growing of subsistence crops eh potatoes on terraced
Description of Richter scale?
11th March 2011
9.0 on Richter scale
100km easy of Sendai on Honshu
10m in height
What are the general primary effects of earthquakes?
Buildings collapsing
Roads and bridges being destroyed
Buckling of railway lines
What are seismic waves?
Waves produced in an earthquake
Explain the formation of a composite volcano?
Plates move towards eachother due to convection currents
The denser oceanic plate subducts beneath the continental plate
Melting occurs in this zone due to frictions and heat and magma forms
This increase in pressure is released in an explosive eruption along the flat
Giving a steep sided volcano
What did L’Aquila measure on the Richter scale?
6.3
General uses of fold mountains?
Farming
Mining
Tourism
HEP
What did Italian government do to prepare for the earthquake?
Civil protection department
Trains volunteers
Laws on construction standards
Formation of oceans of trenches?
As oceanic subducts beneath continental
A very deep steep sided depression is made
Very deep sea causes an ocean trench
Characteristics of a composite volcano?
Steep sided Hardens quickly Thicker Less viscous Slower Explosive Less frequent
Why do plates move?
Due to convection currents
How do tilt meters help to monitor volcanos?
They record the slightest change in the shape of the land
What caused Japan tsunami?
Pacific plate subducts under North American
Earths crust flicked up between 5-10n
Example of a destructive zone?
The Pacific plate su ducts under the Eurasian plate
This causes many large earthquakes in Japan
Where do most tsunamis occur?
Subduction (destructive margins) zones
Earthquakes at destructive plate boundaries (subduction)
Higher magnitude earthquake
Where were the responded to Haiti?
UN troops distributed aid and kept order
Red cross set up temporary field hospitals
Iceland sent rescue teams
Dominican Republic provided water and medical supplies
Cash for work in clearing rubble
After one year still 1,300 camps
Small farmers supported for crops
Continental crust features?
Thicker Older Permanent Floats Less dense
