Tectonic hazards Flashcards
(20 cards)
What are the x4 processes that drive tectonic plate movement?
- Slab pull
- Seafloor spreading
- Subduction
- Mantle convection
Explain the process of convection currents
The core heats the magma which travels up to the crust, begins to cool and sinks back down.
What directions do the plates move at a divergent plate boundary and what occurs?
Divergent plates move away from each other and shield volcanoes occur.
Which type of plate boundary produces the most explosive volcanic eruptions and why?
Convergent plate boundaries and a higher silica level making it more viscous.
What is the Benioff zone?
Caused at a convergent plate boundary where the oceanic plate subducts under the continental plate.
What are volcanic hotspots?
An isolated magma plume in the upper mantle. eg Hawaii.
What are intraplate earthquakes?
Occur in the middle or inferior of tectonic plates or on ancient fault lines.
What are the x3 different types of seismic waves and which one causes the most damage?
Primary,Secondary,Love. Love waves do the most damage.
Are earthquakes or volcanic eruptions easier to predict, and why?
Volcanoes because there are a lot more warning signs e.g ground tremors, sulphur dioxide is released, shape of land changes because of magma rising.
What is palaeomagnetism?
The record of geomagnetic data preserved in minerals and rocks. Some minerals can become magnetised parallel to the the Earths magnetic field.
What is sea floor spreading?
The formation of fresh areas of oceanic crust which occurs due to the upwelling of magma at mid ocean ridges and otward movement
What is slab pull?
A force that results from denser oceanic plates sinking beneath less dense continental plates along convergent boundaries and subduction zones.
What are pyroclastic flows?
A dense fast moving flow of solidifies lava pieces, volcanic ash and hot gasses.
What is the hazard risk equation?
Risk = Hazards x Vulnerability / Capacity
What evidence can be used for sea floor spreading?
Palaeomagnetism
What direction do the plates move in at a conservative plate boundary and what processes occur?
The plates slide past each other and earthquakes occur.
What is the PAR model?
The Pressure and Release model explains how disasters are shaped by structures and processes different in space and time.
What are the tow scales used to measure earthquakes?
Mercalli Scale and the Moment Magnitude Scale.
What is used to measure volcanic eruptions?
Volcanic Explosivity Index
