1º British: Earthquakes and volcanoes

As we studied last week, the crust or litosphere is one of the most interesting and active layers of out planet because it is NOT form by a sigle piece but on the contrary, there are different plate tectonics (such as giant pieces of a puzzle) floating over the semi-solid magma from the mantle. And when two of these plates move towards each other (when they collides like a car crash) or when two of these plates move apart from each other, the magma rises throught the gap: a volcanic eruption! 

Watch the following videos by Dr.Binocs Show. They are both very short and easy to understand:

Video 1. Volcano

Video 2. Earthquake

There are areas in the planet which more probabilities of suffering both volcanic eruptions and earthquakes. This is because they are localted in the area known as “the Pacific ring of fire”.

The Ring of Fire has 452 volcanoes and is home to over 50% of the world's active and dormant volcanoes. In fact, 90% of the world's earthquakes occur along the Ring of Fire. One of the most famous of them is the Krakatoa, in Indonesia. And it has woke up just several days ago! Its explosion was so strong and powerful that it was heard almost 600 kilometers away!

But here in Europe we have also some sadly famous volcanoes such as Mount Vesuvius, the one that destroyed the Roman city of Pompeii in the year 79. In this link you can watch a 8-minute animation video about the last day of Pompeii. 

So, if they are so dangerous, why do people still live near volcanic areas? Because volcanoes can bring people many energetical and economical benefits:

1. The ash deposited during a volcanic eruption adds valuable nutrients to the soils and helps to fertilise it. This helps agriculture and farming

2. They also provide mineral resources (eg.gold, copper, etc.), pumice and building materials.

3. Volcanic landscapes are very attractive for tourism.

4. In volcanic areas, electricity can be generated from geothermal energy (free heating!).

What we have to do is to learn how to predict volcanic eruptions and seismic waves, to prepare an evacuation plan in advance, to save the people before anything happen. Now a days there are several tools:

• Gas measurements (sulphur dioxide & carbon dioxides increases as magma rises)
• Seismic readings (earthquakes increase and become shallower as magma rises)
• Webcams and Satellite imaginery (measures “bulges” as magma moves up the volcano)
• Temperature / acidity of soil and water (they both increase as magma rises) 

For predicting earthquakes we use a seismograph, a machine that detetcs the tremors of the Earth. By reading its graph we can see the strengh/danger of the arthquake:

  

The strength of the tremors is called magnitude. We measure the magnitude with an instrument called a seismograph and we create scales with the information obtained. One of the best-known scales is the Richter scale.

Task 1. Short questions (as usual)

Now, to show that you have really revised all that information (if necessary, you can also do a quick online search), send the answers to the following questions to blogeducativo08@gmail.com before Monday, 27 April:

Question 1: What is a volcano?

Question 2: What is the difference between magma and lava?

Question 3: How does a volcano erupt?

Question 4: Name the different types of volcanoes

Question 5: How is called the surface where two tectonics plates slip?

Question 6: What is a tsunami?

Task 2. Science project!

Well then but... if we are not taking exams this term, how are we be evaluated? Good question! I've prepared a very special activity: How to make your own volcano at home! This activity will give you a mark that cover the 20% of your final score this term. Click on the link to read all the instrutions, see the examples and the delivery date.