Layers of the Earth
List the three main layers of the Earth **from smallest to largest**.
crust
core
mantle
The movement of molten rock in the asthenosphere that moves the tectonic plates. (Hint-two words)
Convection Currents
List the three types of volcanoes.
Shield Volcanoes
Cone Volcanoes
Stratovolcanoes
What two types of plate boundaries are likely to produce earthquakes?
Convergent and Transform plate boundaries.
What is density?
Density = mass / volume
The lithosphere is made up of what two layers of the earth?
crust and top-most part of the mantle.
What is the name of the supercontinent that existed ~320 million of years ago?
Pangaea
What type of volcano is only found in the ocean and forms islands?
Shield Volcanoes
What are three ways scientists use Seismic Waves to gather information?
1. Learning about the interior of the earth.
2. Strength of an earthquake (or similar event).
3. Locating the epicenter of an earthquake (a method called triangulation).
What is subduction?
Subduction is the process of a more dense layer going UNDER a less dense layer.
There are two types of crust which can be differentiated by their densities. What are the two types and which is more dense?
Oceanic (more dense) and Continental (less dense)
What do we call the plate boundary where two plates collide?
What landform(s) is created in an oceanic-continental collision?
What landform(s) is created in a continental-continental collision?
Convergent Plate Boundary
- oceanic-continental boundaries create deep ocean trenches and volcanoes due to subduction
- continental-continental boundaries create mountain ranges
What type of volcano is the most explosive and most common?
What makes these volcanoes so explosive?
Stratovolcanoes! They are especially explosive due to water vapor and dissolved gasses.
What causes the S-wave Shadow?
S-waves can only travel through solids. So the shadow is created by the liquid metal outer core that the s-waves cannot pass through.
Match the type of volcano to the type of magma it's made up of.
Stratovolcano Granite
Shield Silica
Cone Basalt
Stratovolcanoes are made up of magma rich in SILICA.
Shield Volcanoes are made up of magma rich in BASALT.
Cone Volcanoes are made up of magma rich in GRANITE
The earth's core has two layers. What do we know about each?
The Outer Core is made of liquid iron and nickel. Its motion creates the Earth's magnetic field.
The Inner Core is solid iron due to pressure. It turns a little faster than the rest of the Earth (~one extra turn every 1,000 years!).
What do we call the plate boundary where two plates are moving apart?
What landform(s) is created in an oceanic-oceanic boundary of this sort?
Divergent Plate Boundary
Mid-ocean ridges and formed.
What type of volcano creates the larges pillar of smoke and is composed of layers of ash?
This type of volcano is only found on one type of crust-which type?
Cone volcanoes.
Cone volcanoes are only found on continental crust.
What causes the P-wave shadows?
Refraction or BENDING of the P-waves in the liquid outer core layer due to a difference in density.
Why are Earth's layers in the order we find them?
Gravity has the greatest pull on high density materials. So the dense metals get pulled to the center of the earth and less dense rock surrounds it.
The mantle makes up 84% of the earth's volume. What are the four layers of the mantle and what is special about each?
Lithosphere-shared with the crust, makes up the tectonic plates.
Asthenosphere-molten rock/magma that moves in convection currents.
Transition Zone-has a lot of water in the form of H+ and OH-.
Lower Mantle-...the lowest part of the mantle.
Alfred Wegener came up with the Theory of Plate Tectonics. What were three pieces of evidence he used to support this theory?
-sea floor spreading
-similar plant fossils on different continents that are now separated by an ocean and in different climates
-similar animal fossils on different continents that are now separated by an ocean and in different climates
-similar rock layers and rock formations on different continents that are now separated by an ocean
Aside from being formed as plate boundaries, volcanoes can also be formed above especially warm areas in the earth's mantle. What are these warm areas called?
Hot Spots
What is the different between the focus and the epicenter of an earthquake?
The focus is the location in the crust of earth where the event that caused the earthquake occurred.
The epicenter is the location on the surface of the earth directly above the focus.
Explain what sea floor spreading is and how it provides evidence for the Continental Drift Theory.
At divergent plate boundaries, magma rises from the asthenosphere creating new sea floor (or adding to the oceanic plate). Therefore, the oceanic crust closest to the boundary is newer and the oceanic crust further from the divergent plate boundary is older.