Moving plates of Earth's crust cause massive alterations to the landscape. The three biggest effects of plate tectonics are:
This unit will look at each of these in more depth.
Let's start with volcanoes:
The two types of magma are Mafic and Felsic
The magma is molten core and oozes up from Earth's interior until it breaks through the surface and erupts.
This molten core is composed of mostly heavy metals and is loosely bonded.
This hot molten rock is loosely bonded so the gases escape and the lava flows. It looks like this:
That flowing makes a gentlly shaped volcano called a "shield volcano" that looks like this:
You will notice that this type of magma is hot, dark, thin, and friendly. They are found where molten core breaks through the surface (divergent boundaries and hot spots).
Felsic is melted sea floor which is found at subduction zones of some convergent boundaries. It is light colored, cooler (600 C), but much thicker which means the gases bring the lava with them when they explode out (think shaken soda can).
When this ash settles back down, the volcano forms a classic shape called a "stratovolcao":
Sometimes the magma doesn't erupt. When that happens, the molten plume gets called an "igneous intrusion." They are worth looking at more closely:
Dikes, Sills, Laccoliths, and Batholiths are important.
Simply put all an earthquake is is anything that shakes the earth. There are millions of earthquakes each year resulting from the crustal plates sliding past one another.
Note the Focus and the Epicenter
The energy released travels in the form of waves:
P-waves are the fastest and go through anything. They are compressional.
S-waves are second to arrive and go through only solids. They are transverse.
Surface waves are last to arrive. They only travel a short distance and only at the surface of the Earth. They do all the damage. They are Love or Rayleigh waves.
We can measure these waves with seismograms:
You need three of these readouts for each of the three dimensions.
But some places don't feel the earthquake.
Any guesses why?
Notice the Surface waves only travel a short distance and the S waves cannot travel through the core.
The S-waves do not go through liquids and so die at the outer core.
The P-waves get bent at the cores and, as you can see, have an band around Earth that they do not reach.
There is a lot of energy released when the Earth shakes:
It is measured:
Notice that slope. What that means is that each number is 10x as strong as the previous number!
The third effect of tectonic movements is mountain formation. There are three processes that create mountains. They are convergent collisions of continents, volcano production, and dome mountains.
Yes, that is a laccolith that bulges the land above it. It produces a mountain or mountain "range" that is dome shaped:
Contrast Mafic and Felsic
Define the igneous intrusions
Describe the three types of earthquake waves
What are the three mountain making processes