Chapter 1- The Earth Flashcards
Mantle
The mantle consists of hot soft rock called magma and is around 4000 degrees
Crust
The crust is the earths outer skin and consists of solid rock.
Core
The core is made up of iron and nickel and reaches over 5000 degrees
Magma
The melted material that makes up the earths mantle
Plate Tectonics
Earths crust is broken into many pieces and is moving constantly
Plate Boundaries
Where a plate starts and ends
Destructive Boundary
When 2 plates collide the heavier one is forced to downwards into the mantle
Constructive Boundary
When 2 plates pull apart magma rises and creates a new crust
Convection currents
The hot core heats up the magma in the mantle and this creates convection currents
Pangaea
The continents began as one large landmass called Pangaea
Continental drift
When plates move with continents that is how e.g. Europe and Africa is formed this way
Mid ocean ridge
Mid ocean ridge is and underground mountain range it is formed when a constructive boundary occurs
Crater
Mouth of the volcano
Vent
Magma reaches the surface through a vent
Magma reservoir
Where the magma is held before erupting
Active
The volcano is still erupt regularly
Dormant
The volcano hasn’t erupted in hundreds of years but could erupt again
Extinct
Volcano has erupted in over a 1000 years
What is an earthquake
An earthquake is a sudden movement or trembling of the earths crust
Fault line
The plates move along the fault line
Tremor
Spread out from the focus
Focus
The DEEP point in the earths crust where the earthquake begins
Epicentre
It’s the point directly over the focus on the surface where the tremors are the strongest
AfterShock
It’s a smaller tremor that occurs hours or days after the main earthquake
What is a Passive Boundary
At this boundary two plates past each other and if the plates jam tension builds up and when this tension(energy) is released an earthquake occurs
Mount St.Helen WHERE? Most recent eruption Build up to eruption Huge volcanic eruption Aftermath
Rocky Mts,Washington State, USA
July 2008
small earthquake,ash stream and small lava flows out of crater.
Gas,stream,ash,lava,rock
Destruction,60 ppl died and destroyed forest
The negative and positive effects if volcanoes
N- death,destruction and ash clouds
P- tourism and fertile land
Seismometer
Seismometer - a pen on the tip of the seismometer records tremors on a rotating drum
Richter scale
Uses seismometer to measure the intensity of an earthquake of its magnitude, it is a scientific scale
Metrically scale
Isn’t a scientific scale. It describes intensity of an earthquake
Sichuan earthquake WHERE WHEN STRENGTH PLATES INVOLVED 3 effects
Sichuan,China May 2008 7.9 magnitude Eurasian and Indian -5million people homeless -12million animals killed -70k people killed
Tsunami
A huge wave that is occurred by a underground earthquake
Fold mountain e.g
The nazca and s.american collide at destructive boundary
The rocks that lie on the plates are compressed and forced upwards
The layers of rock buckle and crack into folds.
Alpine fold mts
WHEN?
EXAMPLES
30-35 million years ago
The Andes,Rockies and Himalayas
Armorican
WHEN?
EXAMPLES
250million years ago when African and American plates collide
McGillicuddy reeks, Comeragh and Galtee.
