Earthquakes and tectonic plates Flashcards
What is a destructive plate?
These occur when an oceanic crust meets a continental crust
What is a constructive plate?
Where magma rises it creates new ocenic crust. Ocenic plates moving apart
What is a conservative plate
Plates move, thats it
What is a collision plate
when two continental plates collide
What is the crust made out of
Its solid and made out of granite and basaltic rock
What is the matle made out of
its a semi- solid and its made of silicate materials
What is the outer core made out of
its a liquid and made out of iron and nickel
What is the inner core made out of
solid, and its made out of iron and nikel
Where and what is the epicentre
epicentre is the place directly above the focus
What causes an earthquake
- when plate margins move past each other and get stuck
- then they lock causing pressure
- then the pressure is suddenly removed in a jerky movement which causes an earthquake
P wave
not strong usually the foreshock
S wave
Secondary wave, strong and is the main earthquake
What is Richter scale
the scale on which the strength of the earthquake is measured
What is a seismometer
An instrument used to measure the strength of the earthquake
Describe aftershock
Smaller earthquakes after the main, larger one
What is magnitude
How strong an earthquake is
Describe focus
The place in the earth where rocks are moving which is directly below the epicentre, energy radiating from the focus forms seismic waves
what is the definition of tectonic plates?
the crust broken into large sections
What are the 2 theories about the movement of tectonic plates?
conventional currents and slab pull/ridge push
describe the convection currents theory
currents that occur within the molten rock in the mantle, created by heat rising and falling, acts like a conveyor belt to the plates to make them move in different directions.
describe the slab pull and ridge push theory
Slab pull/ ridge push is the idea that gravity is acting on the plates and pulling them apart
how are earthquakes measured?
On the Moment Magnitude Scale (MMS) on a scale from 0-10 it measures the total amount of energy released by earthquakes
Describe and explain the distribution of earthquakes
include:
. main plate boundaries (North+ south American, Nazca, centre of the Atlantic and Ring of Fire)
. occurring in a linear pattern
. happen on plate margins as that is where plates move
. movement make earthquakes more likely
. larger earthquakes are on destructive plate boundaries
where is the Peru-Chile trench?
Along the west coast of South America
