Tectonic Hazards Flashcards
What is the order of the layers of the earth ?
Crust
Mantle
Outer core
Inner core
Describe crust
Thinnest, lowest density
Describe mantle
Thick, denser than crust
Describe outer core
Made of molten iron and nickel
Denser than the mantle
Describe inner core
Made of solid iron and nickel
Densest layer
Describe continental crust
Thicker
Less dense
Made of granite
Describe oceanic crust
Thinner
Denser
Made of basalt
What are the 4 plate margins ?
Collision
Destructive
Constructive
Conservative
Describe collision margins
2 continental plates
Converging
Describe conservative margins
2 plates move alongside
Pressure builds up
When plates slip-pressure releases -earthquake
Describe constructive margins
2 plates diverging
Magma rises through the gap- volcanos
Lava solidifies- new crust
Describe destructive margin
2 plates: continental + oceanic
Converging
Oceanic dives beneath continental, as its denser
Known as subduction
Can cause earthquakes+ volcanoes eruptions
What is an epicentre of the earthquake ?
The point of the earths surface directly above the focus, in theory, shacking here will be stronger
What is a focus of the earthquake ?
The point underground where the plate slip, and from where the seismic waves radiate outwards
.
Smaller earthquake that occur in the hours,days,weeks and month following the main event, caused by the plates slipping a little more as they settle down into their new configuration
What is a fault line of an earthquake
A fracture in the rock at a plate margin where pressure builds up if the moving plates stick
What are seismic waves ?
Energy waves that radiate out from the focus and cause the ground to shake . Primary waves stretch and compress the ground, whilst secondary waves shake in from side to side
What is magnitude ?
Th higher the magnitude, the more energy is released and the greater the potential for damage to buildings and people
What is Richter scale ?
Amount of energy released by an earthquake and the intensity of shaking
What is magma chamber ?
A reservoir of molten rock within the crust, below the volcano. When this starts to rise towards the surface, an eruption becomes more likely
What is a vent ?
The “pipe” that connects the magma chamber to the crate. Magma rises up the vent before erupting
What is a crater?
A depression at the top of the volcanic cone from which lava, ash and other products are emitted
What is a parasitic cone ?
A smaller cone that develops on the side of the main cone. It forms is the main vent is blocked, and rising magma follows smaller channel to be erupted from the side of the volcano
What is a primary hazard ?
Direct consequence
What is secondary hazard?
Indirect consequence
Example of a primary hazard of earthquake
Ground shacking and displacement
Example of secondary hazard of earthquake
Tsunami
3 reasons why people want to live in areas of volcanic hazards ?
Volcanic ash breakers down to form fertile soil, making it easy to grow crops
Volcanoes bring valuable minerals such as sulphur
Volcanic landscapes attract lots of tourist
3 physical factors that effects the severity of hazard impact during an earthquake
Magnitude
Geology
Distance from epicentre
Depth of focus
3 human factors that effect the severity of hazard impact during an earthquake
Population density
Time of the day
Lever of development
