Australia and Volcanic Activity

Australia has no current volcanic activity to date. Although there was volcanic activity that was recorded within Southern Australia around 5,000 years ago. The nearest active volcanoes to Australia rest in Papua New Guinea, New Zealand, and Indonesia.

One well known volcano "Whakaari", rest on a neighboring island near New Zealand called White Island. It is a popular tourist attraction because much of the geothermal active occurs under the water and other activity can be observed from the surface. The most recent eruption occurred on December 9th, 2019 and injured and killed a great deal of tourists visiting the island. The volcano itself is quite volatile and has been placed on alert level 2, meaning the volcano isn't quite ready to erupt but is high in volcanic activity.

Sources:

https://www.abc.net.au/news/2019-12-12/new-zealand-white-island-volcano-eruption-how-it-unfolded/11789586

http://www.australasianscience.com.au/article/science-and-technology/australias-volcanic-history-lot-more-recent-you-think.html

https://www.ga.gov.au/scientific-topics/community-safety/volcano

Australia's Seismicity and Fault movements

(Common Earthquake hotspots)

Seismic activity is defined as the different types, sizes, and frequency of earthquakes that occur in a certain area over a certain period of time.

Australia lies in the center of the Indo-Australian tectonic plate and is not near any other plate boundaries. This means that Australia has a relatively low amount of seismic activity, yet low seismic activity does not mean that Australians don't experience strong earthquakes. It just means that they experience large earthquakes after longer periods of time.

Seismic studies have shown that Australia experiences earthquakes of magnitude 7 around every 100 years. More common earthquakes in Australia occur every 5-10 years and are recorded at a magnitude of 6. It is very unlikely for Australia to have an earthquake that is larger than magnitude 8 because those quakes mainly occur at plate boundaries. Most of the earthquakes occur under the surface at a distance of 20 km, which compared to other countries seismic activity is considered quite shallow.

The geology of Australia mainly consists of old, cold, and dry rocks that rest on the surface. They do not absorb seismic activity very well so earthquakes can be felt at a long distance. Earthquakes of a magnitude of 6 or greater have been observed to break the crust.

The majority of buildings within Australia before the 1990's were not prepared for earthquakes. It wasn't until the 1989 newcastle earthquake, where 13 Australian's lost their lives, that Australia decided to create new construction standards.

Sources:
https://knowledge.aidr.org.au/resources/ajem-april-2019-earthquakes-happen-in-australia-but-are-we-prepared/
https://www.src.com.au/earthquakes/seismology-101/earthquakes-in-australia/

Australia in Respect to Plate Tectonics

Plate Tectonics is the process of the earths lithosphere moving, shifting, and changing in accordance to the placement of crustal plates. Each country is close or near to its regions tectonics plates and is affected by certain geologic activity. As you can see Australia currently rests in the center of the Indo-Australian Plate which is one of the 7 major tectonic plates. It borders other plates in the north, south, and east, such as the Eurasian plate, Antarctic plate, and the pacific plate.

The Australian plate is moving approximately 7 cm each year and is known to cause violent earthquakes to its neighboring countries like New Zealand. The Indo-Australian plate is also credited to raising the Himalayan mountains because of convergent plate boundaries colliding with each other.

Convergent Boundary: Plates moving towards each other and colliding.

Sources:

https://www.australiangeographic.com.au/topics/science-environment/2011/10/earthquakes-in-australia/

https://earthhow.com/indo-australian-plate/

Keller,Edward A., and Duane E. DEVecchio.Natural Hazards. Fourth ed., Routledge, 2016. 

Hazards, Disasters, and Catastrophes

Whenever a natural disaster occurs like a tornado, hurricane, or earthquake I hear some similar terminology being used. Usually I hear the words disaster or catastrophe get thrown around, while the word hazard is used for more commonly understood dangers. Honestly, I thought that many of these words meant the same thing, that something quite terrible and out of our control has occurred. Yet I've come to learn that terms Natural hazard, Disasters, and catastrophe describe different states of danger and damage that is inflicted on human life.

First off, a Natural Hazard is the natural processes or events that pose a threat to both human life and property. Many of us experience these natural hazards in the form of earthquakes, flash floods, hurricanes, Many of these events are repetitive and may occur seasonally over a certain area depending on the time of year. Therefore these hazards are natural events that occur freely whether we are the cause of them or not.

Second, A Natural Disaster is a hazardous event that occurs for a limited time over a specific area. I think that it is important for us to understand that natural disasters are the result of natural events or hazards that occur within nature. A great example of a natural events turning into disasters would be the result of a flash flood after a heavy rainfall. 

Lastly, A Catastrophe A massive disaster that requires significant expenditure of money, time, and resources. I think that one of the most commonly discussed catastrophes is that of the earthquake that rocked Haiti in 2010. Hundreds of thousands of lives were both lost and affected due to the state of Haitis architecture and ways of living.

Sources:
https://www.tulane.edu/~sanelson/Natural_Disasters/introduction.htm

Keller, Edward A., and Duane E. DeVecchio. Natural Hazards. Fourth ed., Routledge, 2016.