Experts believe Upper Hunter earthquakes were not caused by mining activity

By admin • 成都桑拿 • 18 Sep 2019

Fault line: The fault, known as the Hunter-Mooki Thrust, forms the boundary between the Sydney Basin Rocks and the New England Fold Belt to the north.Movement in afault line that runs through the Hunter Valley is the most likely explanationfor a series of earthquakes that have rocked the Upper Hunter over the past week.

The fault, known as the Hunter-Mooki Thrust, forms the boundary between theSydney Basin Rocks and the New England Fold Belt to the north.

A Geoscience spokeswoman said the fault may have been reactivated due to a build-up of pressure.

“While this feature has not been the subject of detailed earthquake study, it is favourably oriented for reactivation in the current stress field,” she said.

“A possible continuation of the thrust offshore Newcastle shows significant earthquake-related uplift across it.”

Geoscience recorded seven earthquakes near Muswellbrook rangingfrom 2.1 to 3.5 on the Richter Scale between last Thursday and Monday.

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Another earthquake shakes the Upper HunterThe spokeswoman said seismic activity in the Hunter was not surprising, with90 earthquakes recorded in the region over the past decade.

They include 19 earthquakes that have occurred within 50 kilometres of Muswellbrook since last January.

The director of n Centre for Astrobiology at the University of NSW, Martin Van Kranendonk, said it was unlikely the recent earthquakes were the result ofmining activity.

“Earthquakes are much more likely to be the result of movement in the crystalline structures of the earth,” ProfessorVan Kranendonk said.

“If it was a mining-related earthquake it would almost certainlybe a one-off event. You might get a little bit of uplift but that would be it,” he said.

ProfessorVan Kranendonk said it was common for richore seams to be found along geologicalfault lines.

The Geoscience spokeswoman said mine sites were not monitored for seismic activity.

“The National Earthquake Alerts Centre monitors earthquakes across using a national network of seismometers,” the spokeswoman said.

“Monitoring of individual mine sites for low levels of seismicity is not an activity that Geoscience is engaged in.”

Warkworth resident John Krey said it was difficult to distinguish between an earth tremor and a mining blast.

“If it’s a blast then you are kind of relieved that it’s done for the day,” he said.

NSW Minerals Council chief executiveStephen Galilee said thenumber of coal mines operating in the Hunter had fallen by a quarter since 2012.

Warkworth resident John Krey

“All mine blasting in the Hunter is conducted under strict regulation and with public safety as the first priority,” he said.

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