Flashcards in Chap 1 Gateway 2 Earthquakes and Volcanic eruptions Deck (29)
What is an earthquake?
It is a vibration in the earth's crust caused by a sudden release of energy stored in the rocks found along fault lines
Why does the earthquake occur?
When there is a plate movement along plate boundaries
What does plate movements cause?
A slow build-up of stress on the rocks found on either side of the fault
What happens the rocks can no longer withstand the stress in a plate movement
They suddenly slip many metres causing the the earthquake
What energy does earthquakes release
Seismic waves radiate out from a point of sudden energy called?
What is the epicentre?
It is point on the earth's surface directly above the focus
What follows after an earthquake event
Smaller earthquakes called aftershocks
What are different types of earthquakes
Where is the location of deep-focus earthquakes?
Between 70 and 700 km below the earth's surface
Where is the location of shallow-focus earthquakes?
In the upper 70 km of the earth's crust
What is the impact of the deep-focus earthquakes?
Smaller impact on the land as seismic waves take a longer time to reach the surface
What is the impact of the shallow-focus earthquakes?
Greater impact on the land as seismic waves reach land surface more quickly
What scale is used to measure the magnitude of earthquakes?
What are factors aside from magnitude of earthquake to affect the extent of damage?
Level of preparedness
Distance from the epicentre
Time of occurance
Type of soil
Where does earthquakes occur?
At convergent, divergent and transform plate boundaries
Which plate boundary does earthquakes occur most and why?
Convergent, because more stress occurs builds uo when a plate subducts beneath another
What is the machine that records the seismic waves?
What are the risk associated with living in earthquake zones?
Disruption of services
Destruction of properties
Destruction of infrastructures
Loss of lives
What causes volcanic eruptions?
Tectonic activity that occurs on land and on sea
In regards to volcanic eruptions, how do we classify volcanoes?
What are the risks of living near volcanic areas?
Massive destruction by volcanic materials
What are the different types of destruction from volcanic eruptions?
What are the different types of pollution from volcanic eruptions?
Thick plumes of volcanic ash
Release of gases such as carbon dioxide, sulfur dioxide
Fine ash particles can travel afar and cause serious damage to aircraft engines
What are the benefits of living near volcanic areas?
Precious stones and minerals
What the types of crops that the fertile soil of Bali and Java support
What are the types of precious stones that volcanic rocks contain?
What is an example of tourism that a volcanic area provides?