Quake activates dormant fault line
Sunday’s 5.7 magnitude earthquake could pave the way for more tremors in the area over time and additional equipment has now been deployed to monitor the activated fault.
Geoscience Australia senior duty seismologist Dan Jaksa told the Times the quake was “unusual” in that it was an intraplate event (not on a tectonic boundary) and there had been no other events in that location since recording began about a century ago.
“When an earthquake occurs in a region, the probability of another . . . is increased because the fault there has become active and along the fault there is the possibility of triggering other events,” he said.
“You find stresses in Australia because the plate is moving north-east about 7cm a year towards Papua New Guinea where it collides with the fastest moving tectonic plate on Earth, the Pacific Plate.”
Mr Jaksa said it was impossible to predict when and where tremors would occur, but confirmed Geoscience Australia had now set up six additional temporary monitors and hoped for realtime data streaming.
“The idea of doing the aftershock deployment is to get a better feel of the fault that has been activated here,” he said.
There have been a series of aftershocks, most imperceptible and occurring on the same day.
The initial 5.7 magnitude quake between Kojonup and Walpole was among the biggest in WA’s history and felt right across the southern part of the State.
Yallingup’s Annie Palmer felt two tremors, the first of which was stronger.
“It woke my husband who was asleep, but we live in a steelframed house so likely to get more of a tremor than one on a slab in Lagoon Drive,” she said.
Gnarabup’s Stacey Watts said it took some time to figure out what was happening.
“I could feel the couch moving and at first I thought it was a strong gust . . . then I realised it was an earthquake,” she said.
Residents as far as Perth reported feeling the quake but there were no reported injuries.
I could feel the couch moving and at first I thought it was a strong gust . . . then I realised it was an earthquake. Stacey Watts