Topic 1 - 1 Marker Flashcards
What are the main characteristic processes operating at destructive plate
boundaries?
Subduction occurs where two plates converge. Subduction can lead to
the formation of features such as deep sea trenches and island arcs.
Which of the volcanic hazards is being appropriately managed?
In certain types of eruptions, lava can be safely channelled away from
places of high risk. This can be achieved using explosives and
artificially dug channels.
Which is the most significant natural factor leading to the spread of a wildfire?
Prolonged periods of drought and high rates of evapotranspiration,
especially in the summer months in sub-tropical climates. A strong
dry wind increases the risk.
What are the characteristics of tsunamis?
They have a long wavelength and low amplitude. They travel at high
speeds, sometimes over 700 km/h. Shallow water and the funnelling
effect of bays dramatically increases height.
What is an appropriate measure to tackle the spread of wildfire?
Use of retardants combined with controlled burning can contain a
wildfire, provided this is well planned and co-ordinated in advance
of the event.
what is an island arc?
Where oceanic plates collide, subduction leads to increased friction
and melting. The less dense material begins to rise through the crust,
creating a series of volcanic islands.
what is the process of slab pull?
At destructive margins gravity forces lithosphere to descend into the
mantle. The collision with the other plate causes both shallow and
deep seismic activity.
what is the method for measuring the size of a volcanic eruption
A logarithmic scale which offers an indication of the explosiveness of
events. It is a way of classifying events by volume of material
produced and frequency of events.
In the context of natural hazards, what is meant by the term
fatalism?
This is a view that outcomes of future hazards are beyond the
power of people to control. Individuals, families and
communities take little action to mitigate against hazards.
what is risk sharing as a human response to a hazard
Government or private companies offer insurance against the
impact of the hazard. It requires large numbers to purchase
the insurance compared to those impacted following the
event.
how do tropical storms lead to storm surges
The storm conditions lead to the formation of tsunami waves
which are extremely large in size. These can be over
20 metres in size and inundate the coast where they strike.
How does an earthquake lead to liquefaction?
Loosely packed, water-logged sediments at or near the
ground surface lose their strength in response to strong
ground shaking. This acts like a fluid for the duration of the
vibration.
