AN EARTHQUAKE IN AUSTRALIA Australia has a relatively low rate of seismicity due to its location towards the centre of the Indo-Australian Tectonic Plate. Earthquake activity is much higher around the margins of the Indo-Australian Plate, for example In places such as Indonesia, Papua New Guinea and New Zealand. Nevertheless, many historic earthquakes have Occurred in Australia and Geosciences Australia’s database (QUAKES) contains information on tens of thousands Of historic earthquakes in the Australian continent. Most of these, however, have been in areas of low population Density.
Australian earthquakes are termed ‘interpolate’ earthquakes because of their distance from the more active Plate boundary. Models to explain the origins of Australian earthquakes need much more development and, in The interim, the occurrence and nature of Australian earthquakes is incompletely understood and poorly Described. This incomplete understanding leads to uncertainties in descriptions of the earthquake hazard facing The Newcastle and Lake Macquarie study area. Prior to events such as the 1968 Meckering earthquake and the 1989 Newcastle earthquake, Australia was thought to be relatively safe from this particular natural disaster.
Several Damaging earthquakes have impacted upon Australian communities in the last 50 years. The 1989 Newcastle Earthquake dominates the damage and casualty statistics. The 1989 Newcastle earthquake prompted a re-examination of earthquake activity in the Hunter region. Prior To this event, the earthquake history of the region was forgotten, lost or ignored, apart from perhaps the memory Of 1925 Boolaroo earthquake in older residents. For example, the effects of the 20 June 1868 Maitland Earthquake had been documented (Clarke, 1869) but had passed into insignificance.