Tuesday 29 April 2014

Magnitude 4.7 Earthquake in South Australia.

Geoscience Australia recorded a Magnitude 4.7 Earthquake close to the ground surface about 258 km northeast of Adelaide in South Australia, slightly before 7.55 pm local time (slightly before 9.55 am GMT) on Tuesday 29 April 2014. This is the largest Earthquake recorded in South Australia for 20 years, and was felt across much of the Mid North and Flinders Ranges, however it's epicenter was in a remote location, and there are no reports of any damage or casualties.

The approximate location of the 29 April 2014 South Australia Earthquake. Google Maps.

The precise causes of Earthquakes in South Australia are often unclear (at least in part because these events are somewhat rare, limiting the amount of data available to seismologists). The Flinders Ranges are ancient fold mountains, formed during the Delamerian Orogeny in the Late Cambrian and Early Ordovician (between about 514 and 500 million years ago), an episode of mountain building driven by a collision between Australia and southern Africa during the formation of the supercontinent of Pangea. These mountains contain many deep faults, and Earthquake activity in the area is likely to be connected to movement on these faults. However the area also contains large areas of poorly consolidated sediments, which can result in movement in an Earthquake being more intense at locations far from the moving fault than occurs on the fault itself, making the identification of moving faults very difficult.

Witness statements can help geologists to understand Earthquakes and the geological processes that cause them; if you felt this quake (or if you were in the area but did not, which is also useful information) you can report it to Geoscience Australia here.

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