Restless Earth Flashcards
Age of oceanic crusts
200 million years old
Age of continental crusts
1500 million years old
Properties of oceanic crusts
Denser, newer, younger, can be subduction, can be renewed and destroyed
Properties of continental crust
Older, less dense, cannot be subducted, cannot be renewed or destroyed
Oceanic plate subducts beneath continental plate
Destructive subduction
Two continental plates move together
Destructive collision
When plates move away and hot magma fills in the gaps between
Constructive
Two plates sliding along each other
Conservative
Where plates meet
Plate margins
The more explosive volcanoes in a cone shape
Composite volcanoes
Boob shaped volcanoes which are much less of a threat
Shield volcanoes
What melts the plate as it subducts underneath a continental plate?
Friction
What can usually be linked with destructive subduction margins when the plates rub together under the surface
Earthquakes
Usually next the a volcano on a destructive subduction margin
The sea
The name of the current which makes the hot magma rise
Convection current
Reason why magma rises
Gaseous rocks under the volcano, convection currents
An example of a destructive subduction boundary
Juan de Fuca plates subducts beneath North American plate
When the crust is nor created or destroyed
Conservative
An example of a conservative plate boundary
San Andreas Fault
Constructive plate boundaries are usually under…
Water
Constructive plate boundaries move
Apart
Over many years this may happen to constructive plate margins
Islands may break through the surface water
Shield volcanoes are usually created on a … boundary
Constructive
The name of the tectonic plates
North American, Nasca, South American, Eurasian, African, Indo-Australian, Pacific
Structure of the earth
Inner core, outer core, mantle, crust
Usual thickness of tectonic plates
0-60km thick
The Inner core is made from which two metals?
Iron and nickel
Name of a depression usually found on the oceans floor
Geosyncline
Size of young fold mountains
Taller
Size of older fold mountains
Smaller (after being eroded)
An example of fairly new fold mountains
Rocky Mountains (USA), Himalayas (Bhutan/Nepal), the Andes
How mountains are created
Destructive collision, destructive subduction
How Ocean trenches and fold mountains are made
Destructive subduction
How young fold mountains are made
1) rivers deposit sediment in the geosynclines
2) rivers sediment is then compressed
3) plates are forced together at destructive margins
4) sedimentary layers are forced upwards into fold mountains
Ocean trench example
Mariana Trench
Age of the Alps
Approximately 40 million years old (fairly young)
Highest peak in the Alps
Mont Blanc in France (4810 feet)
Uses of fold mountains
Mining, farming, hydroelectric power, tourism
Austria has a large amount of … Deposits in their mountains
Gold
Type of mining where they cut into the Rock from the side
Drift mining
Mining accesses…
Valuable minerals and materials
Main type of farming in the Alps
Dairy farming
When the farming moves his/her cattle due for the season and climate
Transhumance farming
Seasons of transhumance farming
Winter = lower on the mountains/ valleys (due to the harsh climate at the peak i.e. Snow and rain
Summer = top of the mountain ( due to the snow have melted)
V shaped valleys lead to good sites to make
Hydroelectric power stations
Main source of tourism in the Alps
Skiing
The water in dams spins a …
Turbine
Team which monitor volcanoes world wide
USGS
Eruption on the 18th May 1980 at 8:32AM
Mt St Helens, USA
State of which Mt St Helens is located
Washington State
Mt St Helens is a … Volcano
Composite
Total damage of the Mt St Helens volcano
57 people killed, 250 homes destroyed, 47 bridges, 15 miles of railway broken
Size of the exclusion zone which was ignored by the press at MSH
8km
MSH earthquake reading on Richter scale
5.1
Five ways of monitoring a volcano
COSPEC, tilt metres, seismographs, GPS, digital cameras
The very top of the volcano
Caldera
Bellow a caldera in a volcano lies the…
Magma chamber
COSPEC uses what type of sensors to indicate when the eruption is about to occur
UV measures the amount of sulphur dioxide release
Tilt metres detects
Lava domes
Tilt metres are tiny and if they were 1km long they could record a change in level of…
1mm
Digital cameras record the ash/dome…
Visually - which is safe and effective
GPS uses … to detect earth movement
Satellites
GPS systems also detect…
Heat
How many GPS systems were installed in MSH?
12
Seismographs detect…
Earth quakes around volcanoes which could contribute towards the eruption.
Seismographs sends information to … To make…
Machines to make squiggly lines
Type of magma released from a shield volcano
Basalt
Type of magma released from a composite volcano
Andesite
Capital of Haiti
Port Au Prince
Strength of Haiti earthquake
7.0
Reasons why so many people died
- densely populated city
- unprepared
- building laws ignored
Number of people who died in Haiti earthquake
A reported 250,000
The fraction of buildings collapsed
1/3
Number of inmates escaped after the Port Au Prince prison was broken
4000
Secondary effects of Haiti earthquake
Cholera and typhoid spreaded
Responses to Haiti earthquake
- uncoordinated emergency services mobilised
- people left to search for their own family and friends
- country inaccessible for aid
- hospitals overwhelmed by number of casualties
Number of ambulances mobilised after Haiti earthquake
1
Long term responses to the Haiti earthquake
- 1.5 million people in temporary accommodation
- city not rebuilt fully
Haiti is an example of an…
LEDC
Earthquake example in an MEDC
Kobe, Japan
Date of the Kobe earthquake
17th January 1995
Strength of the Kobe earthquake
7.2
Number of people who died in the Kobe earthquake
5,500
Number of people injured in the Kobe earthquake
30,000
Name of the bay which Kobe is located in
Osaka Bay
Name of the motorway which collapsed in Kobe
The Hanshin Expressway
Name of the fault in Kobe which lead to an earthquake
Nojima fault
