“The lockdown was an absolute, I hesitate to use the word ‘sending God’, but it was certainly a factor in avoiding injury.”
Minor damage was worse along Chapel Street, where aging buildings sit on loose sediment from the Yarra River that amplifies surface waves during an earthquake.
Sediments are generally stable, but aging, unreinforced buildings above them could be vulnerable, as geological, engineering and architectural conditions align.
Melbourne’s building code requires new commercial buildings and residential towers to be able to withstand an earthquake of magnitude between 6.5 and 7; but there are no rules for houses, nor for buildings built before 1989.
“An event like the one we just experienced is actually a bit of a wake-up call to go back and look at things like that, figure out what our earthquake risk is? And what is the risk associated with these unreinforced buildings? Said Doctor Duffy.
Many people believe that because Australia sits in the middle of its tectonic plate, it is largely immune to earthquakes, said Professor Priyan Mendis, who is on Australia’s Earthquake Standards Committee.
But the Australian plate is moving north and steadily getting stuck between other plates, gradually compressing the country. This pressure builds up over time – before it is suddenly released due to a fault.
âPeople think we are safe – we are not safe. We will see more severe earthquakes in the future, âsaid Professor Mendis.
Dr Duffy said Victoria was capable of sustaining a magnitude 7 earthquake, although this was extremely rare; other experts put the likelihood of a magnitude 6 earthquake hitting Melbourne at one in 1,000. Dr Duffy said authorities should prepare for this scenario and consider which buildings need to be reinforced and who will pay. for that.
Aging buildings could be upgraded to withstand earthquakes, as they did in Christchurch, he said.
In Melbourne, Flinders Street station suffered “seismic reinforcement” during recent conservation work by Lovell Chen for Development Victoria.
Professor Mendis said tall buildings are actually quite flexible and tend to be more secure.
People should stay indoors and take shelter under a table or door frame during an earthquake. Buildings are unlikely to collapse and most injuries occur outdoors from falling debris.
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