Cause
In early 2007 a United States academic claimed that coal mining in the region triggered the earthquake, although earthquake activity has been present in the area at least since white settlement first occurred. This is in addition to reports by the former head of Geosciences Australia's earthquake monitoring group, Dr David Denholm, who stated that the Newcastle earthquake was some distance from mining activity:
"The depths of the focus of the earthquake was about 13, 14 kilometres, whereas the ones associated with mining, they're actually right close to the mine, because that's where the stress release takes place".
Despite this, even the most recent earthquake codes required neither the adoption of earthquake resistant design regulations in Newcastle, nor the strengthening of old buildings, although they did encourage owners to provide more than the minimum strength.
Read more about this topic: 1989 Newcastle Earthquake