According to leading geologists, an earthquake 30 times more powerful than the devastating quake that struck Christchurch in 2011 could strike Adelaide.
Geoscience Australia has been digging trenches along the Willunga fault line in South Australia, revealing evidence of past significant seismic activity.
Dr. Dan Clark said a massive earthquake could strike the surrounding area, including the state capital, dwarfing the 6.2 magnitude earthquake that struck New Zealand 11 years ago, killing 185 people.
‘We estimate that an earthquake of magnitude 7.2 could occur along the fault’s 55-kilometer active length,’ he told Adelaide Now.
‘An earthquake of this magnitude would release roughly 30 times the energy released by the Christchurch earthquake.’
Due to its location on a series of fault lines, including the Willunga, Para, and Eden faults, Adelaide is one of Australia’s most seismically active cities.
Adelaide was jolted by a 5.2 magnitude earthquake in March 1954, the largest on record. Three people were seriously hurt as a result of the incident.
In the last ten years, the city has experienced ten earthquakes with magnitudes greater than 3.0, including the 3.7 earthquake in March.
While experts are unable to predict when a major earthquake will strike Adelaide, evidence suggests that large events occur ‘every few hundred years or every 100 years,’ according to experts.
‘We haven’t seen the largest earthquakes that can be generated in most places in Australia,’ he said.
‘Even if these events are rare, critical infrastructure, facilities, and the community as a whole should be prepared.’
‘A magnitude 6.2 earthquake of the magnitude of the Christchurch earthquake, for example, may occur once in a thousand years or once in a few thousand years.’ And earthquakes the size of the 1954 Adelaide quake may occur once every few hundred years or once every century.’
Geoscience Australia has been digging trenches along the Willunga fault line in South Australia, revealing evidence of past significant seismic activity.
Teams from Geoscience Australia, the University of Melbourne and Seismology Research Centre have been excavating two deep trenches to investigate the Willunga Fault, which sits 40km south of the city.
They are seeking for layers of silt that have been shifted by major earthquakes in the vicinity, which may be dated to identify roughly when the event took place.
The data can be used to better prepare areas for possible earthquakes and seismic activity.
Dr Clark said it should be particularly useful for future planning for development, advising against building hospitals, dams and power stations near at-risk regions.
‘While the techniques are not novel in plate margin settings like California or New Zealand, few faults in Australia have been studied this way,’ Dr Clark said.
‘In Australia, researchers have identified over 350 fault scarps – the landscape features produced by large earthquakes – mostly via desktop studies using digital elevation data.
‘Fewer than a dozen of these faults have been the subject of detailed paleoseismic field investigation to determine their actual seismic potential.’