On Friday 22 June 2012 at a little after 7.15 pm local time (a little after 9.15 am GMT) an Earthquake shook occurred New South Wales, centered roughly 110 km north of Canberra and 200 km west of Sidney and at a depth of about 10 km, according to Geoscience Australia, who measured the quake as 3.8 on the Richter Scale. Such a quake could potentially have been felt over a fairly large area, but is unlikely to have caused any significant damage or casualties.
Map showing the location of the 22 June quake. USGS.
Australia is probably the least Earthquake-prone of Earth's continents, since none of the margins of the tectonic plate on which the continent sits comes close to the continental landmass, but still suffers the occasional quake. The southeast of the continent is affected to some extent by spreading on the margin between the Antarctic and Australian Plates far to the south, and movement on the margin between the Australian and Pacific Plates to the southeast; this is both a subduction zone and a transform margin, the Pacific Plate is being subducted beneath the Australian Plate, and at the same time the Australian Plate is rotating relative to the Pacific Plate, pushed by the movement on the Antarctic Plate margin. The area has seen two larger quakes this week, in Victoria on Tuesday 19 June and on Macquarie Island earlier on 22 June, and it is likely that this quake is an aftereffect of one or both of those larger quakes.
See also Earthquake shakes Macquarie Island, Melbourne shaken by Earthquake, Canberra shaken by mild Earthquake, Central Australia hit by major Earthquake and Earthquakes on Sciency Thoughts YouTube.
Follow Sciency Thoughts on Facebook.