Australia’s ageing transportation networks are in need of a “comprehensive” seismic risk assessment, Risk Frontiers says in a briefing note.

While the country does not have a high seismic hazard level, large earthquakes can nevertheless still occur and cause significant damage because of the low ground motion levels used in the design of structures, according to the catastrophe loss modeller.

“Many parts of the network are ageing and may not have been designed with modern seismic considerations in mind, making them susceptible to damage during an earthquake," the briefing note says.

“By evaluating the seismic vulnerability of transportation networks, we can identify areas that require immediate attention and devise strategies to mitigate the risks.”

Commonwealth agency Geoscience Australia says on average 100 earthquakes of magnitude 3 or more are recorded in the country each year.

The agency says quakes of magnitude 5.0 or higher, such as the 1989 Newcastle earthquake, occur on average every 1-2 years, and about every 10 years the country could expect a potentially damaging earthquake of magnitude 6.0 or more such as the magnitude 6.5 earthquake that shook the WA wheatbelt town of Meckering in October 1968.

An Insurance Council of Australia (ICA) report released this month said the 1989 Newcastle quake would result in losses of $6.54 billion if it struck today. The revised figure from an original $862 million is calculated by Risk Frontiers and based on new data to assess the expected present-day impact of past insurance catastrophes by “normalising” the cost.

The Risk Frontiers briefing note says Sydney is one of the most suitable candidates for performing seismic risk analysis since the country’s biggest city has a reliance on various bridges for connecting different locations.

“Such an analysis is expected to yield insightful outcomes, providing a detailed understanding of how the city’s transportation network might respond to earthquakes and providing guidance on options for suitable mitigation strategies,” the briefing note says.

“This approach ensures that the transportation network remains resilient and functional, even in the face of unexpected seismic events, thus safeguarding the connectivity and accessibility that are vital to Sydney’s urban landscape.”

The briefing note says performing the seismic risk analysis for a transportation network provides the means required to expand the methodology to investigate the effects of other perils such as floods on the same grid.

“This way, cities can be more resilient, which ensures the continuity of essential services and saves lives during disasters,” the note says.

Click here for the briefing note.