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UNIDAD 2: CONTINENTES Y OCÉANOS


ACTIVITY 8: EARTHQUAKES AND VOLCANOES

 

1. Read the text:

What causes earthquakes and where do they happen?

The Earth has three major layers: the core, mantle and crust.  (figure 1) The crust and the top of the mantle make up a thin skin on the surface of our planet. This skin looks like a puzzle on the surface of the Earth, with many different pieces (figure 2). The pieces move around very slowly, sliding past one another and bumping into each other. We call these puzzle pieces tectonic plates, and the edges of the plates are called the plate boundaries. The plate boundaries are made up of many faults (fig. 3), and most of the earthquakes around the world occur on these faults.

 

 

 

 

 

 

 

 

 

                                        Figure 1

Figure 2

 

 

Figure 3

 

 

 

 

2. Read the text:

How are earthquakes recorded?

seismographEarthquakes are recorded by instruments called seismographs. The recording they make is called a seismogram. (figure 4)  The seismograph has a base that sets firmly in the ground, and a heavy weight that hangs free.  When an earthquake causes the ground to shake, the base of the seismograph shakes too, but the hanging weight does not.  The difference in position between the shaking part of the seismograph and the motionless part is what is recorded.

 

 

 

Figure 4

Can scientists predict earthquakes?

No, and it is unlikely they will ever be able to predict them.  Scientists have tried many different ways of predicting earthquakes, but none have been successful.  On any particular fault, scientists know there will be another earthquake sometime in the future, but they have no way of telling when it will happen.

Information from: http://earthquake.usgs.gov/

3.Visit the following  Internet link and answer the questions in your notebok:

             Clich here

 

 

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