If you’ve ever been stuck on that roundabout near Parliament House, you may have noticed hard evidence of earthquakes. Keep your eyes on the road, but in that exposed rock cutting you can easily see fault lines caused by two large earthquakes more than 6.5 in magnitude.
Stay calm; they occurred millions of years ago but earthquakes are an unpredictable beast, which is why researchers at the ANU are doing ground-breaking research to be better prepared.
In a first-of-its-kind experiment, ANU researchers are shooting lasers down fibre optic cables (like Internet cables) to sense and record what’s happening below the Earth’s surface.
While Canberra has its own nearby fault line (the Lake George fault scarp conveniently located just 25 kilometres away), the ANU is experimenting on the Alpine Fault in New Zealand.
ANU Professor Meghan Miller says the active nature of the Alpine Fault makes it ideal to study using a technique called distributed acoustic sensing (DAS).
“I don’t know of any other DAS experiment like this being done across a major active plate boundary,” Professor Miller said.
“We know major earthquakes – magnitude 7.5 or 8 – occur along the Alpine Fault on average every 260 years. The last one was about 306 years ago so there is a significant chance of a major rupture in the next 50 years, which makes the experiment all the more critical.”
This experiment uses 8,000 individual sensors across the fault rather than just one or two seismometers spaced tens or thousands of kilometres apart. This delivers an extraordinary amount of data – roughly one gigabyte per minute.
“We can’t predict earthquakes, but we can better prepare for them. This is one of the ways we can prepare – by getting more information about faults and how earthquakes rupture.”
While this research may seem a long way from home, earthquakes do occur here, with more than 140 recorded within 100km of Canberra in the past 10 years.
According to Geoscience Australia, 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.
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