Twin earthquakes shake northern New South Wales
13 June 2012
The Queen's birthday weekend started with a shake for residents in north-western New South Wales as two earthquakes hit the area in quick succession on Friday night.
The magnitude 4.2 and 4.1 earthquakes occurred at 9:31pm and 9:32pm respectively on 8 June 2012 approximately 20km west of the township of Manilla, and 25km north-east of Gunnedah.
"Geoscience Australia has received over 500 individual reports from residents as far as 100km away from the epicentre describing how they felt the two events", said Seismologist, Dr Jonathon Bathgate.
"We recorded six aftershocks in the four hours following the two main earthquakes and all have been very small in magnitude", he said.
"In the past 100 years, there have been 13 earthquakes greater than magnitude 4 in the area, with the most recent being a magnitude 4.6 earthquake in February 1983", said Dr Bathgate.
These earthquakes are called intra-plate, and occur due to the release of stress that has built up in the Earth's crust, caused by movement of the tectonic plates. The Australian continent is part of the Indian-Australian plate which is being pushed slowly north-east at approximately 8cm per year. South Australia is being slowly squeezed sideways by about 0.1mm each year.
For the latest earthquake information please see Earthquakes @ Geoscience Australia.
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