Physical Processes & Tectonic Hazards Flashcards
1
Q
What are seismic waves?
A
The released energy radiated through the earth
(The movement felt during an earthquake is the result of seismic waves)
2
Q
Primary P waves
A
- Body wave
- Fastest
- Reaches the surface first
- Travels through liquids & solids
- Causes backwards and forwards shaking
- Least damaging
3
Q
Secondary S waves
A
- Body wave
- Slower than P waves
- Only travel through solids
- Causes a side-way motion
- More damaging
4
Q
Love L waves
A
- Surface wave
- Slowest
- Causes side to side motion
- Larger and energy is focused on the surface
- Most damaging
5
Q
What is a primary hazard?
A
A direct result of an earthquake
6
Q
What is a secondary hazard?
A
A result of the primary hazards
7
Q
Primary hazards of earthquakes
A
- Ground shaking
- Crustal fracturing (when the movement causes the Earth’s crust to crack)
8
Q
Secondary hazards of earthquakes
A
- Landslides and avalanches: the movement of the Earth may trigger the collapse of material down slopes
- Liquefaction: Shaking cause particles in the ground to move further apart causing them to act like a liquid and not a solid
- Flooding: caused by tsunami
9
Q
Primary hazards of volcanoes
A
- Pyroclastic flow: Mix of dense, hot, rock, ash and gases
- Lava flow: Can reach over 10000 degrees
- Ash falls: Can travel long distances, can kill
- Gas eruptions: Gases trapped in magma are released causing gas clouds which are hazardous to health
10
Q
Secondary hazards of volcanoes
A
- Lahars: Mix of rocks, mud, and water flowing down the volcano, fast flowing, destructive
11
Q
Formation of a tsunami
A
- When an earthquake occurs beneath the sea bed this leads to a tsunami
- Water is displaced and forced upwards causing a wave
- Wave height increases
- As the wave reaches the shore, the water recedes back out to sea
- ## Tsunamis usually occur close to plate boundaries
12
Q
Causes of tsunamis
A
- Landslides: could displace the water
- Underwater volcanic eruptions
