Experts say the earthquake that shook Mount Barker and surrounds yesterday as was the largest to occur within 30km of Adelaide in over a decade.

More than 12,600 people felt the tremor from Victor Harbor to Kapunda, Marino to Mypolonga.

While significant earthquakes are rare in South Australia, they do happen, including the 1954 earthquake in Adelaide which was 50 times larger. 

One of Geoscience Australia's Senior Seismologists, Phil Cummins, joins Jennie Lenman to discuss.