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Mountains, Volcanoes, & Earthquakes images

Moving plates of Earth's crust cause massive alterations to the landscape.  The three biggest effects of plate tectonics are:



Mountain formation

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

Mafic                                           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.

Image result for magma from core


This hot molten rock is loosely bonded so the gases escape and the lava flows.  It looks like this:

Image result for mafic lava

Image result for mafic lava


That flowing makes a gentlly shaped volcano called a "shield volcano" that looks like this:

Image result for shield volcano


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).


Hot spots:

Image result for hot spots, hawaii




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).

Image result for subduction zone

Image result for felsic eruption


Image result for pyroclastic flow


When this ash settles back down, the volcano forms a classic shape called a "stratovolcao":

Image result for stratovolcano





Sometimes the magma doesn't erupt.  When that happens, the molten plume gets called an "igneous intrusion."  They are worth looking at more closely:

Image result for igneous intrusion

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.

Image result for earthquake waves

Note the Focus and the Epicenter


The energy released travels in the form of waves:

Image result for earthquake 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:

Image result for earthquake waves

You need three of these readouts for each of the three dimensions.


But some places don't feel the earthquake.

        Any guesses why?


Image result for earthquake waves

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:

Image result for earthquake energy


It is measured:

Related image

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.


Continent collision:

Image result for continent continent collision




Image result for volcano creation:



Dome mountain:

Image result for dome mountain

Yes, that is a laccolith that bulges the land above it.  It produces a mountain or mountain "range" that is dome shaped:

Image result for adirondack mountain range




Quick review:

Contrast Mafic and Felsic
    How hot?
    Where found?
    Volcano shape?
    Danger level?

Define the igneous intrusions

Describe the three types of earthquake waves

What are the three mountain making processes

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