Tectonic Hazards Flashcards
Are tectonic hazards a type of natural hazard?
Yes
What is a natural hazard?
A naturally occurring event that has the potential to affect people’s lives or property
Name a couple examples of natural hazards?
Earthquakes, tsunamis, volcanic eruptions
The earths surface is separated into…
Tectonic plates
Describe the 4 layers and the structure of the earth and what they are made out of
- Inner core - solid nickel and iron
- Outer core - liquid
- Mantle - semi-molten rock that moves very quickly
- Crust- very thin, divided into tectonic slabs
What are the two types of crust?
- Continental
* Oceanic
What type of crust is thick and less dense?
Continental
What crust is thin and more dense?
Oceanic crust
The plates are moving because…
The rock in the mantle underneath them is moving
The places where the plates meet are called the ____ or _____
Boundaries or plate margins
What are the 3 types of plate margin?
- Destructive
- Constructive
- Conservative
The area where continental plates collide is called a …
Collision zone
Destructive margins are where two plates are… explain
Moving towards eachother.
Where an oceanic plate meets a continental plate, the denser oceanic plate is forced down into the mantle and destroyed.
What’s an example of a destructive margin?
Pacific plate is being forced under the Eurasian plate along the east coast of Japan.
Constructive margins are where two plates are… explain
Moving away from eachother.
Magma (molten rock) rises from the mantle to fill the gap and cools, creating new crust.
What’s an example of a constructive margin?
The Eurasian plate and the North American Plate are moving apart at the mid-Atlantic ridge
Constructive margins are where two plates are….. explain
Moving sideways past eachother.
or are moving in the same direction but at different speeds. Crust isn’t created or destroyed.
What’s an example of a conservative margin?
The Pacific plate is moving past the North American plate on the west coast of the USA
What’s a fault?
A fracture in the earths crust that shows signs of movement
What’s the subduction zone?
Area of destructive plate boundary. The plate does under another.
Do earthquakes occur at all three plate margins?
Yes
How is an earthquake caused at a destructive margin?
Pressure builds up when one plate gets stuck as it’s moving down past the other into the mantle
How is an earthquake caused at a constructive margin?
Pressure builds up along the cracks within the plates as they move away from eachother
How is an earthquake caused at a conservative margin?
Pressure builds up when plates that are grinding past eachother get stuck
What are shock waves?
Vibrations that cause an earthquake
What is the focus?
The point in the earth where the earthquake starts
What is the epicentre?
The point on the earths surface straight above the focus
Near the epicentre the shock waves are…
Stronger and cause more damage
The amount of energy released by an earthquake (its magnitude) is measured using…
The Richter scale
Are volcanoes found at all three types of plate margin?
No, only destructive and constructive plate margins
