A magnitude 4.8 earthquake just shook southeast Victoria. Here’s why we may expect more |
At just after 2am on Saturday morning, a magnitude 4.8 earthquake occurred at Arawata, about six kilometres northeast of Korumburra and 100km southeast of Melbourne.
Residents closest to the epicentre described a loud bang – a phenomenon which occurs only in the epicentral region of an earthquake, when seismic energy reaches the surface.
They also described houses and windows rattling, and trees swaying back and forth as a result of the strong shake. The earthquake was also experienced across the state of Victoria, waking many people from their sleep even as far away as Shepparton, Ballarat and Warnambool. Geoscience Australia received more than 21,000 reports within hours.
The earthquake was followed by hundreds of aftershocks, the majority too small to be felt. The largest so far was a magnitude 3.1 less than an hour after the main shock. These aftershocks, which by definition only occur near the epicentre, are still happening several days later.
Although earthquakes can and do happen anywhere in Australia, the Gippsland region of Victoria has heightened seismic activity relative to most other places. But why is this the case?
Gippsland’s shaky history
In the last 100 years, there have been about ten earthquakes in Gippsland of about the same size or larger than the one at Arawata last weekend; on average, that’s about one every decade, though they haven’t always........