Plate Motion
Alfred Wegner developed the idea of the continental drift. What is the continental drift?
Extra 50 pts. if you can tell me what made his idea flawed.
The continents were once together, and slowly drifted apart.
He had no explanation of how this occurred.
Ocean crust vs Continental crust
Ocean curst- underwater and more dense
Continental crust- lighter and thicker
What are the 3 types of stresses that can be enforced on Earth's crust?
Tension
Shearing
Compression
Will a higher silica count create an explosive or quiet eruption? How do you know?
Explosive.
the magma is thick and sticky building up pressure causing it to burst.
Subduction
Sinking movement of the ocean floor back into the mantle. Occurs at Ocean trenches
What was the name of the supercontinent?
Pangaea
region in the Pacific Ocean that has a lot of volcanic activity and earthquakes.
What 2 things can cause a tsunami? How can they cause a tsunami?
Earthquake and Landslide
They both cause displacement of water.
Where can volcanoes form?
Convergent boundary
Divergent boundary
Hot spots
lava eruptions happen frequently without a boundary present.
comes from the mantle plume as plate is moving
Give two types of evidence that the supercontinent existed long ago.
Plant fossils found on 5 continents
Dinosaur fossils found 2 continents
Mountain ranges lining up from different continents
What does the theory of plate tectonics explain?
It gives an explanation of how the plates move.
List the 3 types of Seismic waves and describe them.
P waves (primary waves)- first to arrive and travel the fastest
S waves (secondary waves)- slower and arrive after primary waves
Surface waves- P and S waves reach the surface and cause the most damage
Name two tools that volcanologist use to determine if a volcano will erupt?
Seismograph- rumbling deep inside volcano
Tiltmeter- measures swelling as magma chamber fills
Anticline and Syncline
Anticline- fold in rock that bends upward
Syncline- fold in rick that bends downward
Why is the Pacific ocean shrinking?
The subduction zones are recycling crust back into the mantle faster than it's being created.
How do convection currents help move Earth's crust/plates?
The heating rock rises and cooler rock sinks in the mantle, forming currents that move the plates.
What does the magnitude scale measure for an earthquake?
Energy released- x32
Explain the magma a quiet eruption vs explosive eruption.
Quiet- Low silica, HOT, and Runny/Thin magma
Explosive- High silica and Thick/sticky magma
Ocean Trench and Mid-ocean ridges
Mid-ocean ridge- area where sea-floor spreading takes place creating long chain of new crust.
Ocean trench- undersea valleys that are in the deepest part of the ocean.
Explain the pattern of new rock forming relating to sea-floor spreading.
New rock is forming as the sea floor spreads at an ocean ridge. It's then pushing the older rock outward making new space for the new rock coming from the mantle.
List the three types of boundaries, and how they move.
Divergent boundary- moves away
Convergent boundary- towards each other and collide pushing plates up/down
Transform boundary- moves along side each other
Name the 3 types of boundaries, faults, and stresses that go together.
Convergent, reverse, and compression
Divergent, normal, and tension
Transform, strike-slip, and shearing
List at least 4 types of volcanoes and give an explanation of each.
Composite- made up of lava and ash.
Cinder cone- mix of bombs, ash, and cinders in layers.
Lava Plateau- lava flowing in cracks of Earth's crust building layers.
Shield- slow and steady eruption with lava flowing over widespread area. Hotspot tend to be shield volcanos
(Final Jeopardy) Explain the structure of a volcano, how an explosion can develop, and what happens when a volcano erupts.
Structure- Magma forms in the chamber in the mantle moving upward into the pipe. Once it leaves the volcano it's turned into lava.
Explosion develops- Thick and sticky magma sticks to the sides of the volcano building pressure.
Quiet eruptions allow the lava to flow gently
Explosive eruptions hurl out lava bombs, ash, and cinders.