Earthquakes

Were you lucky enough to feel the earth tremor in the past couple of months? Although the excitement cannot be replicated, cool websites can help bring the experience back to life.

Firstly, let’s talk about what exactly happened back on the 19th of June 2012. At precisely 8:53pm, a magnitude 5.4 earthquake struck 16 kilometres southwest of Moe in the state’s southeast. There were no reports of injury; however damage to shops and houses were recorded from the earthquake felt within a 250 km radius of its epicentre near Moe. It is the largest earthquake in the state since November 1982 when another magnitude 5.4 earthquake occurred near Wongungarra, 100 kilometres north of the recent event.
(Source: Geological Society of Australia newsletters)

Earthquake epicentre. Source: Herald Sun article 20th June

July 20th marked the largest aftershock recorded since the 5.4 magnitude earthquake struck Victoria’s east.  According to Geoscience Australia, there have been well over 200 aftershocks since the June event with the July 20 earthquake registering 4.4 on the Richter Scale. (Source Geological Society Australia newsletter)

Now some of you may be wondering why Australia is experiencing earthquakes when it lies in the middle of the Indo-Australian tectonic plate? The answer is intra-plate tectonics.

Many will know the basic theory of plate tectonics. The Earth’s surface can be broken up into ‘plates’, as shown in the illustration below.  These plates can move, slide past each other and even collided, all at a very slow rate.  Tension and stress can be created at the plate’s edge.  When they “re-adjust” to release this tension, a large earthquake occurs, such as in New Zealand.  But what if there is no room for the plates to “re-adjust”? The stress builds up within the plate, not just at the edges, until an intra-plate earthquake releases it. In Australia’s case, the Indian-Australian plate is being pushed northeast at a rate of 8cm per year, with South Australia experiencing a sideways compression of 0.1mm each year (Source Geological Society of Australia website).

Tectonic Plates. Source: Wikimedia Commons

Experts such as The University of Melbourne’s own Professor Mike Sandiford agree that the Gippsland area of Victoria is an earthquake “hotspot”, with earthquakes similar to June 19th anticipated approximately every 20 years (Latrobe Valley Express, 22nd June 2012).

“This is a reminder, even though we live in a country with a low earthquake risk, it is not negligible, we do sometimes get earthquakes”, he said (Latrobe Valley Express, 22nd June 2012).

While surfing the internet for more information about the Australian earthquakes, I managed to stumble upon a few websites which are extremely handy those who are interested and intrigued about our daily earth tremors.

For on the spot information about earthquakes, you can’t go past the United States Geological Survey. This website contains real-time information about the time, location, magnitude and depth of every earthquake recorded across the globe. From the comfort of your living room, you can scan the globe, individually picking out earthquakes which may interest you. With the ability to change the data feed from all quakes to only those over magnitude 2.5, this website can keep you entertained for hours!

http://earthquake.usgs.gov/earthquakes/map/
For information specifically about Australian Earthquakes, the Environmental Systems and Services website provides accurate details of both earthquakes and some associated aftershocks.

http://www.esands.com/Earthquakes.html

However my favourite website for earthquakes is: http://www.stumbleupon.com/su/2M51aD/www.niceone.org/lab/quakes

This website allows the user to scan the globe for interesting earthquakes, but it enhances this feature with its bubble scaling tool. By changing the scaling to amplitude, you can get a comparative depiction of the area affected by a specific earthquake. The energy yield scaling feature is exceptionally cool, and I have seen earthquakes where the energy yield fails to fit on the webpage! Remember back to the 5.4 magnitude earthquake on June 19th? Well let’s just say its energy yield paled in comparison to a couple of earthquakes in areas around Alaska and Japan!

So if you have some spare time or a passion for earthquakes, check these websites out. Who knows, maybe you might enjoy them as much as me!

Ps here is comic I found about the Australian earthquakes!