Earthquakes!!

After learning that fault lines can be the sites of earthquakes, we will be spending this week learning about what earthquakes actually are.

• What causes them?
• Why can the be so destructive?
• What are aftershocks?
• Why does liquefaction sometimes occur?

This is a really good link, too: http://sciencelearn.org.nz/Contexts/Earthquakes/Science-Ideas-and-Concepts

This video gives a good overview of what we will be looking at in class:

Focus and Epicentre

What happens within/along the fault line to actually trigger an earthquake?

Earthquake Waves

There are four different types of earthquake waves: two body waves, called P (Primary) and S (Secondary) Waves; and two surface waves called L (Love) and R (Raleigh) Waves. What are their characteristics?

One thing Mr Nicoll forgot to mention in this video was the link between the Richter Scale, Modified Mercalli Scale and the waves:

Richter Scale measures magnitude. This is the amount of energy in each wave pulse. This means each wave has a larger amplitude.

Modified Mercalli Scale measures intensity. This is the frequency of the waves. The higher the frequency, the more seismic waves per minute.'

Aftershocks

One common occurrence after earthquakes is a series of aftershocks. Are these just more earthquakes, or are they something slightly different? Why do they occur?

Liquefaction

In certain soil types, liquefaction is something earthquakes can cause. It can be devastating. What type of soils are susceptible to liquefaction? How and why does it happen?