Geological time scale
What does a geological time scale show?
Changes in the earth
What are plates/ how do they move?
Plates are the earths structure; they move by convection currents
How does a volcano form?
Two tectonic plates push against each other and then form a mountain, and then could become a volcano
Where and why do earthquakes happen?
Where- Happen at late boundaries when pressure builds then is released as the plates move.
Who is Alfred Wegener
1. "Pangea"/ contiental drift
Evidence to support: Land features(mountain ranges), fossils, climate change.
What is uniformitarianism?
uniform
What is the difference between continental plates and oceanic plates?
Continental plates are less dense and thicker, and oceanic plates are thinner and more dense.
What is the diffrence between magma and lava?
Magma- BENEATH the earth's surface
Lava- ON the earth's surface
foreshocks- Before an earthqake
aftershocks- After an earthquake
Who is Harry Hess?
Hess is known for sea floor spreading
Why do we study space objects to find out more about earth?
Because the earths crust is similar to things out in space like asteroids
What are the three types of stress? And what happens at each plate?
1. Divergent- Push apart
2. Transform- Slide past each other
3. Convergent- They overlap each other
Active- is erupting
Dormant- could erupt
Extinct- no longer active
What is the Richter scale?
It compares the size of earthquakes
What evidence do we have of sea floor spreading theory?
1. Molten material
2. Magnetic stripes
3. Drilling rock samples
What is the theory of continental drift?
Wegener: Said that plate tectonics were all once one big plate called the "Pangea"
what is folding and faulting? When does it happen?
Folding- Bends in rock
When does folding happen- Occurs as rocks bend slowly
Faulting- Breaks in the crust
When does faulting happen- Occurs when rocks break
What are the 4 different categories of volcanoes?
Cinder cone- Formed from particles and blobs of lava
Lava domes- Formed by thick lava that hardens right around the vent
Composite- Shaped like a cone formed from layers of lava
Shield- Formed form wide thin layers of lava shaped like a shield
What are seismic waves
An elastic wave in the earth cause by an earthquake
How does a deep ocean trench form?
It happens when two tectonic plates meet and it melts or slides beneath the lithosphere.
What is subduction?
the sideways and downward movement of the edge of a plate of the earth's crust into the mantle beneath another plate.
What are the focus epicenter and hypocenter?
What is the focus?
Epicenter- Point on earths surface vertically above the focus of an earthquake
Hypocenter- The underground focus point of an earthquake
Focus- The pint where the earthquake starts to rupture