Sensors aid in quake knowledge

Tari JeffersManjimup-Bridgetown Times
Manjimup shire community emergency services manager Todd Ridley, Geological Survey of WA Ruth Murdie, Department of Fire and Emergency Services’ Leon Gardiner and DFES senior intelligence analysist Justin Whitney with the earthquake sensor about to be embedded into the ground.Picture: Tari Jeffers
Camera IconManjimup shire community emergency services manager Todd Ridley, Geological Survey of WA Ruth Murdie, Department of Fire and Emergency Services’ Leon Gardiner and DFES senior intelligence analysist Justin Whitney with the earthquake sensor about to be embedded into the ground.Picture: Tari Jeffers Credit: Tari Jeffers/Manjimup-Bridgetown Times

Better understanding of seismic activity across the South West is the aim of a project announced last week on the second anniversary of the 5.7 magnitude Lake Muir earthquake.

On Wednesday, representatives from Geological Survey of Western Australia, Department of Fire and Emergency Services and Shire of Manjimup visited the Manjimup site of a recording station, which will improve data, monitoring and analysis of earthquakes and tremors.

A total of 25 recording stations will be installed in the South West by the end of October.

One of the recording stations has been installed at farmer Mark Muir’s Mordalup property, which is a few kilometres north of the earthquake epicentre from two years ago.

Mr Muir said he was glad there was interest in coming back and taking notice of the region.

“Any information they can glean from around the area that is earthquake prone is beneficial,” he said.

“There is a lot to learn about what happened.

“Every now and then we feel a rumble but we can’t confirm if it’s a minor earthquake or a truck going past.”

A 3km surface rupture was reported near the epicentre of the Lake Muir earthquake, but Mr Muir said it did not happen on his property. Within days of the main earthquake in 2018, Geoscience Australia installed portable seismic recording devices and began livestreaming data back to its operations centre in Canberra.

More than 700 aftershocks were recorded, including a magnitude 4.6 on October 13, 2018 and a magnitude 5.4 on November 9.

Geoscience Australia earthquake hazard lead scientist Trevor Allen said a number of key observations and lessons were learnt from the information collected.

“Based on geological investigations from the Lake Muir area, there is little evidence to suggest previous earthquake activity on this fault in the recent geological past,” he said.

“In Australia, surface-rupturing earthquakes have all occurred on previously unknown faults.

“It is impossible to predict where the next large earthquake will likely occur in the region.”

Department of Fire and Emergency Services strategy and emergency management deputy commissioner Mal Cronstedt said enhanced monitoring was an important part of understanding earthquakes, but the installation should also serve as a reminder for the community to be prepared.

“Western Australia is one of the most seismically active areas in Australia and we generally anticipate a magnitude 5.0 earthquake in the South West every 10 years,” he said.

“Earthquakes can happen anywhere, at any time and have the potential to cause major damage and loss of life — so it’s crucial to be prepared.”

Geological Survey of Western Australia senior geophysicist Ruth Murdie said she wanted to bring earthquake monitoring back to WA.

“We need to understand our State better,” she said.

The collaborative research project was funded by the Australian Research Centre in 2019 and culminated in last week’s recording station installations.

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