What is an earthquake? Imagine this, click on the speaker button (Spilsbury, 2004)  An earthquake is the shaking of the ground as a result of movement of tectonic plates located on the outer layer of the Earth’s surface.  The moving plates send out shock waves that can be strong enough to change the surface of the Earth pushing up rock faces and leaving gapping cracks in the ground.  Cause huge destruction by destroying buildings and structures such as bridges. Breaking power and gas lines and causing fire. Triggering natural events such as landslides, volcanic eruptions and tsunami’s.  Causing loss of life (vtaide, n.d)

What causes earthquakes?  The outer surface of the Earth called the crust is made up of layer solid rock which make the land the (continental plate) and the oceans the (Oceanic plate).  These plates move very slowly around the Earth floating on hot liquid rocks found in the upper mantle.  As the plates move they slide and grind along side each the boundary that they rub along is known as a fault.  This movement is called transform boundaries, sometimes two plates get caught on each other this causes friction and builds up a huge amount of pressure that needs to be released.  The energy is released from the fault in all directions producing seismic waves (Spilsbury, 2004)

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Earthquakes  Where the earthquake begins below the Earth’s surface is called the hypocentre.  The area on the Earth’s surface directly above were the earthquake started is called the epicentre.  Sometimes an earthquake can have foreshocks before the main shock and then after the main shock aftershocks will occur which can lasts for weeks and months after the main earthquake (Spilsbury, 2004).  Earthquakes are recorded on seismographs which make a recording called a seismogram.  The size of an earthquake is called a magnitude (USGS, 2012).  Earthquakes are measured on a Richter scale, which is rated on how much damage an earthquake has caused. The stronger the earthquake the higher the number.

Magnitude Scale

Where do earthquakes occur?  Earthquakes can happen all around the Earth on continental plates and oceanic plates.  Most of them occur at the meeting of two plates on tectonic boundaries however some can happen in the middle of a plate (Spilsbury, 2004).  Some regions are more prone to Earthquakes than others. The edge of the Pacific plate has frequent earthquakes particularly in areas such as New Zealand, Vanuatu, Solomon Islands, Papua New Guinea, Japan, America and in Indonesia where the Indo- Australian Plate collides with the Eurasian Plate.  Although Australian does not sit on the edge of a plate it can still experience earthquakes because the Indo- Australian plate is being pushed north which makes it bump into the Eurasian, Philippine and Pacific Plates.  Adelaide is at most risk of having an Earthquake in Australia. Interesting fact: “There are on average 80 earthquakes of magnitude 3.0 or more in Australia each year. Earthquakes above magnitude 5.5, such as the 5.6 magnitude event in Newcastle in 1989, occur on average every two years. About every five years there is a potentially disastrous earthquake of magnitude 6.0 or more.” (Australian Government Geoscience, 2012)

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Earthquake and tsunami [Image].(n.d.). Retrieved 25 October, 2013, from 9sUsfLLaiTiQfruIGICQ&sqi=2&ved=0CAcQ_AUoAQ&biw=1438&bih=596#facrc=_&imgdii=_&imgrc=eiEnhXoaAF8m4M%3A%3B9e_lts9Vca- voM%3Bhttp%253A%252F%252Fkoroitfourfive.files.wordpress.com%252F2011%252F03%252F japan- earthquake.jpg%3Bhttp%253A%252F%252Fkoroitfourfive.wordpress.com%252Fearthquake-and-tsunami-photos%252F%3B640%3B360 Earthquake Magnitude scale [Image]. (n.d). Retrieved 25 October, 2013, from e7pYHYBw&ved=0CAkQ_AUoAQ&biw=1438&bih=596#facrc=_&imgdii=_&imgrc=OxODikzFHrDr7M%3A%3B- 4Ih7DH9kHB64M%3Bhttp%253A%252F%252Fi.cbc.ca%252F !%252FhttpImage%252Fimage.jpg_gen%252Fderivatives%252Foriginal _300%252Fearthquake-magnitude.jpg%3Bhttp%253A%252F%252Fwww.cbc.ca%252Fnews%252Fworld%252Frichter-magnitude-scale-explained %252F%3B300%3B391 Marshmallows [Image ]. ( n.d.). Retrieved 25 October, 2013, from QfurYCABQ&ved=0CAkQ_AUoAQ&biw=1438&bih=596#facrc=_&imgdii=_&imgrc=Y1jStoJXVoZkPM%3A%3BVWsAvh20XBkVeM%3Bhttp%253A%252F%252F content%252Fuploads%252F2012%252F10%252Fmarshmallow11__64416_zoom.jpg%3Bhttp%253A%252F%252Fwww.nathantaylor.net.au%252F%253Fp %253D448%3B300%3B223 Richter scale drawing. [Image].(n.d.). Retrieved 25 October, 2013, from iAfHjoGYDw&ved=0CAkQ_AUoAQ&biw=1438&bih=596#facrc=_&imgdii=_&imgrc=FQpUtsVHFqOTWM%3A%3BKBaZG2Bgql16MM%3Bhttp%253A%252F%2 52Fwww.rmmagazine.com%252Fwp-content%252Fuploads%252F2012%252F08%252Frichter- scale.jpg%3Bhttp%253A%252F%252Fwww.rmmagazine.com%252F2012%252F03%252F01%252Fthe-need-for-better-earthquake-protection%252Frichter- scale%252F%3B630%3B455 Richter scale [Image]. (n.d.). Retrieved 25 October, 2013, from ml&h=0&w=0&sz=1&tbnid=wWvzL5Es62FJCM&tbnh=195&tbnw=259&zoom=1&docid=A4_tY2ZGHz-WlM&ei=F2RsUsiVFsjyiAecn4Ao&ved=0CAMQsCU Tectonic Plate motion [Image]. (n.d). Retrieved 25 October, 2013, from a=X&ei=_lVsUvjCDoToiAe404HIDw&sqi=2&ved=0CAcQ_AUoAQ&biw=1438&bih=596#facrc=_&imgdii=_&imgrc=9T0S0dPhZqhTpM%3A%3BReyXJxrEvs53w M%3Bhttp%253A%252F%252Fwww.passmyexams.co.uk%252FGCSE%252Fphysics%252Fimages%252Ftransform_boundaries.gif%3Bhttp%253A%252F%25 2Fwww.passmyexams.co.uk%252FGCSE%252Fphysics%252Ftransform-boundaries.html%3B550%3B390 Toothpicks. (n.d.) [Image]. Retrieved 25 October, 2013, from sUqiLKcm4iAfbw4DACg&sqi=2&ved=0CAcQ_AUoAQ&biw=1438&bih=596#facrc=_&imgdii=_&imgrc=9D1m8Yw5iwmU_M%3A%3B0esPnUgzFl- BGM%3Bhttp%253A%252F%252Fus.123rf.com%252F400wm%252F400%252F400%252Fanitabonita%252Fanitabonita1004%252Fanitabonita % 252F close-up-toothpicks-isolated-on-white-background.jpg%3Bhttp%253A%252F%252Fwww.123rf.com%252Fphoto_ _close-up- toothpicks-isolated-on-white-background.html%3B1200%3B801