Adelaide is often mentioned as one of the cities with mild weather, rarely suffering from major devastation. However, contrary to that image, this is Australia's most likely to experience earthquakes. This risk is not new, but according to scientists, it is still present and can completely flare up in the "predictable future".
The most recent major earthquake in Adelaide occurred on March 1, 1954, with an intensity of 5.4 degrees richter. At the time, it was the most serious earthquake to ever be recorded in Australia. Three people were seriously injured, more than 3,000 buildings were damaged, and about 30,000 insurance records were built due to cracked walls, collapsed chimneys and broken glass doors.
Professor Alan Collins, an expert in the Earth's crust and systems at the University of Adelaide, said another major earthquake was certain to happen in the rest of his life. Maybe this year, 10 years or 20 years, no one knows exactly. But it is likely to happen within that time frame, that is, in the near future, he said.
A study by the University of Adelaide's School of Civil and Environmental Engineering in 2011 estimated that if a similar earthquake in 1954 had recurred at that time, economic losses could reach $1 billion.
Adelaide is located in the area with the strongest earthquake activity in Australia. Under the city's expanded urban area, there are a series of geological faults, including the Willunga fault in the south, para in the north and Eden- burnside running from near Seacliff to the Hills Face Zone.
According to Professor Collins, there is even a crack running through Bonython Park towards Thebarton Theater, cutting through the area where the new tunnel under construction of the Torrens to Darlington project is underway.
In terms of tectonics, the entire Australia is located on the India-Australia stage, including the Indian subcontinent and about half of New Zealand, moving northeast about 7cm per year.
When this plate is pushed from the mountain range between the South Atlantic and collides with other plates, pressure is transmitted through weak rocks including Adelaide and causes seismic activity.
It was the series of earthquakes that lasted for about 3 million years that lifted the Mount Lofty mountain range. These movements do not take place continuously but in a "push-up" manner, each earthquake can push the ground surface up by 1-2m in each period.
In addition to the 1954 earthquake, South Australia recorded a stronger earthquake, 6.5-degree richter near Beachport in 1897. The press at that time described the destroyed houses, the post office and newspaper station collapsed, and the ground cracked right on the main street.
Since the beginning of this year, South Australia has recorded 126 earthquakes, including 3 at 4 richter.
This figure is equivalent to the average of many years. According to Geoscience Australia seismologist Jonathan Griffin, the large or small number of earthquakes is not a sign of a major earthquake coming.
However, experts are in agreement on one point: For Adelaide, seismicity is not a question of whether or not, but of when.
