The Science of Earthquakes

1. What is an earthquake?

• An earthquake is when two blocks of the earth slip past or bump one another.

• The surface where they slip is called the fault or fault plane.

• The location below the earth’s surface where the earthquake starts is called the hypocenter.

• The location directly above it on the surface of the earth is called the epicentre.

• http://www.youtube.com/watch?v=CtBXTvtFaCU

The Science of Earthquakes2.What causes earthquakes and

where do they happen?

• The lithosphere is not all in one piece – it is made up of many pieces called tectonic plates.

• Tectonic plates move slowly sliding and bumping into each other.

• The edges of the plates are called the plate boundaries.

• There are many faults in the plate boundaries and most of the earthquakes around the world occur on these faults.

The Science of Earthquakes3. Why does the earth shake when

there’s an earthquake?

• While the edges of faults slide and bump together create a lot of energy.

• The energy radiates from the fault in all directions in the form of seismic waves.

• The seismic waves start in the hypocenter.

• When the waves reach the earth’s surface is the epicentre.

The Science of Earthquakes

• How are earthquakes recorded?

• Earthquakes are recorded by instruments called seismographs.

• The recording they make is called a seismogram .

The Science of Earthquakes5.How do scientists measure the

size of earthquakes?

• Reading the Richter scale• It measures the shaking on a

scale from the weakest are 1.0 to the strongest can measure 9.0.

6.Can scientists predict earthquakes?

• No, they can’t predict them.• Scientists have tried many

different ways of predicting earthquakes, but none have been successful.

The Science of Earthquakes

• 7. What is a tsunami?

A tsunami is a large ocean wave usually caused by an underwater.

http://www.tsunamiready.noaa.gov/media/Tsunami_know_what_to_do_Rev2.swf

http://www.youtube.com/watch?v=fnvudkaI0Pk