If you ask me, Canberra has few faults, but its biggest one is near Lake George and if you’ve ever driven there, you’ve inadvertently helped to map the Lake George fault line that lies 800m below.

Your car tyres vibrating along the Federal Highway have been used by ANU scientists as a kind of 3D “CT scan” to look at a still-active fault zone that once experienced 7-magnitude earthquakes.

So thank you citizen scientist drivers for exiting (and entering) our fair city because for about 80km of tarmac, you’ve created by default (pun intended) a never-seen-before picture of what lies beneath.

You don’t have to be a rocket scientist to know that earthquakes are unpredictable, but knowing more about this fault line helps ANU researchers learn about the seismic nature of Lake George.

Unlike Canberra, this fault line sees a lot of action and in the past 60 years it has experienced 50 earthquakes ranging in magnitudes from 1 to 3.5.

That’s just a fraction of what it’s capable of – for the past four to five million years it experienced many 7-magnitude earthquakes.

California has the notorious San Andreas Fault; we have the Lake George Fault.

Study co-author, Professor Meghan Miller, said the imaging technique of analysing ordinary traffic noise allowed scientists to study the structure and characteristics of a fault zone in never-before-seen detail.

So while you were driving to Sydney listening to the radio, you were literally creating good vibrations.

ANU scientists used a network of 100 beer can-sized seismometers, placed in the then-dry lakebed and near the highway. Researchers analysed traffic vibrations and used that data to create 3D images, allowing them to peer 800 metres beneath Earth’s surface – similar to doing a CT scan to create detailed medical images of the human body.

Study lead author Dr Chengxin Jiang said that by cross-listening to the data captured by the seismometers, “we’ve created the first detailed picture of the lake’s fault zone, allowing us to better study its structure and seismic characteristics”.

“Earthquake faults can pose serious risks, especially in areas where people live and build. To understand how dangerous a fault might be, scientists need detailed maps of what lies underground,” Dr Jian said. 

“The findings provide us with insight into the size of the earthquakes that occurred in the geologic past on the Lake George fault, and we can compare that fault to other regions that are seismically active today.”

Through no fault of our own, as far as capital cities are concerned, Canberra is one of the highest rated in terms of earthquake hazard because we are situated between known active faults: Lake George Fault and the Murrumbidgee Fault.