1000km fault line could destroy Aussie city
WESTERN Australia - home of the quokka, beach camels and most of the country's outback. And it's also home to one of the biggest fault lines in the world.
Starting in Albany and stretching 1000km to the north is the Darling Fault, one of the longest and most significant fault lines on Earth, formed when India and Australia broke apart millions of years ago.
While a significant earthquake is yet to occur specifically on the Darling Fault, the lengthy crack sits just to the east of the South West Seismic Zone - the region with most of Australia's earthquake activity.
In the past two decades, the zone has recorded 41 significant quakes and residents living in the region are regularly woken by tremors and shakes.
Hugh Glanville, a senior seismologist at Geoscience Australia, said while it may seem that Western Australia is being hit by stronger and more frequent earthquakes, the increased reports on tremors come down to something else.
"Seismic activity waxes and wanes over time but it's becoming more obvious as the population grows. More people are feeling them and reporting tremors," Mr Glanville said.
"We also have more sensitive instrumentation so it's not necessarily more earthquakes but more people being exposed to them and more instruments there to pick them up."
A magnitude 5.6 earthquake struck off the coast of Western Australia on Sunday, near Carnarvon.
The quake, which occurred at a depth of 10km, struck at around 10.30pm Sunday with even Perth residents - more than 1000km away from the epicentre - reporting tremors.
In November, Perth and Albany locals woke to their homes shaking after a 5.4-magnitude earthquake struck in Kojonup, a town that sits between the two cities.
Mr Glanville said it was the sheer size of Western Australia that made it more susceptible to quakes.
"WA is substantially larger than all the other states so it has a large amount of activity. We've seen in the southwest seismic zone that there's been a lot of earthquake epicentres and swarms in that region," he said.
It's been 50 years since Western Australia was hit with one of its biggest earthquakes in history when a magnitude 6.5 quake ripped through the town of Meckering, 130km east of Perth.
It was on October 14, 1968 that the massive earthquake shook the southern half of Western Australia, razing the town's buildings, sending horses bolting and rattling the inside of homes more than 700km away.
Even the devastating Meckering quake didn't top the Meeberrie quake in 1941 which hit 7.2 on the Richter scale.
But the 1941 quake, 500km from Perth, had little impact on people due to its distance from the coast and civilisation.
Mr Glanville said while the Darling Fault was not located in the state's most common earthquake region, there was still potential for a quake there.
"The Darling Fault near Perth is quite a large fault so it could host a very large earthquake," he said.
"Swallowing Perth would be a bit of artistic licence, but a quake there could cause significant damage - similar to the Meckering earthquake that flattened half the town.
"But Australia has had very few earthquakes of that size recorded in modern history. They're quite rare occurrences. It would more likely be a small to medium earthquake that would shake buildings, so it's not impossible but I would say unlikely."
In 2009, UWA geophysics professor Michael Dentith told PerthNow scientists were still trying to figure out why there hadn't been a significant quake on the Darling Fault.
"It's one of the intriguing things about WA geology. We know there is this huge stress because (earthquakes) are occurring inland, but why are they not occurring on the biggest fault?''
But earthquakes don't just come with a risk of damage to people and property - there's also the flow-on risk of tsunamis.
Last month, research from Geoscience Australia showed the threat of tsunamis is one Australia should be taking very seriously.
Its Probabilistic Tsunami Hazard Assessment (PTHA) released this week shows which parts of the country are most likely to be hit and includes data for more than 500,000 possible earthquake and tsunami scenarios in Australia.
The northwest coast of Western Australia is particularly at risk, according to the research, because of proximity to Indonesia's active and turbulent earthquake zone - making it far more likely to be struck than the rest of the country.
The latest tsunami hazard modelling created by Geoscience Australia updates data from a decade ago, and will be used in disaster risk management, evacuation plans and infrastructure planning.
Although the possibility of a tsunami hitting the WA coast remains low, there have been more than 50 recorded tsunami incidents in Australia since European settlement with the largest impacts in that region, Northern Australia Minister Matt Canavan said in a statement on Monday.