While some parts of the country are more likely to experience earthquakes than others, large earthquakes can occur anywhere across the continent, and without warning. On average 100 earthquakes of magnitude 3 or more are recorded in Australia each year.
Although rare, "earthquakes can occur anywhere in Australia," a senior seismologist with Geoscience Australia says, before adding the country "can be at risk of large earthquakes," too.
An earthquake exceeding magnitude 7 occurs somewhere in Australia every 100 years or so. A typical site in Australia will be within 50 km of a magnitude 7 event every 100,000 years or so.
Abstract. Adelaide is the most earthquake-prone capital city in Australia, with earthquakes of a magnitude five to six on the Richter scale occurring frequently enough to be a potential danger.
Earthquakes in Australia since 1950
The strongest earthquake in Australia happened on 05/23/1989 in the Macquarie Station; New Zealand region with a magnitude of 8.2 on the Richter scale.
Tsunami can happen in Australia and can damage our shores, even if they start far out at sea. They appear somewhere around the world about once every two years, but are a little threat to Queensland's coastal communities in terms of major flooding.
Tennant Creek 1988 earthquake now Australia's biggest after Geoscience revises list, ABC News An earthquake recorded near Tennant Creek in the Northern Territory in 1988 is now considered Australia's largest ever, snatching the title from Western Australia.
Unlike other countries such as Japan, New Zealand and Indonesia, Australia does not lie in close proximity to a tectonic plate boundary where large earthquakes can occur. However, communities in Australia can still experience damaging and deadly earthquakes.
Geologists have made the alarming discovery that Adelaide is at risk of being hit by a devastating earthquake with a magnitude of 7.2. They say the discovery means that Adelaide could be subject to an earthquake much stronger than the one that rocked Christchurch in 2011.
When it comes to earthquakes, living in Australia is much safer than other parts of the world, as Australia is well away from tectonic plate boundaries where large earthquakes occur more frequently.
Earthquakes are relatively common in New Zealand, there are approximately 15,000 per year with about 250 being strong enough to be felt, hence the country's nickname the Shaky Isles. In Australia there are approximately 200 earthquakes per year, however most are too weak to be felt.
WA is the most active both in the size and number of earthquakes. One of Australia's largest recorded earthquakes tore through the wheat-growing community of Meckering in Western Australia on October 14, 1968.
The entire country sits on a single techtonic plate, the Australian plate, rather than over a major fault line, however there are many smaller fault lines within the plate and Australia experiences an earthquake similar in size to the recent one in Victoria every one to two years, according to Geoscience Australia.
Current estimates of earthquake risk in the Sydney Basin indicate that on average, there is a 10 per cent chance of ground accelerations exceeding 0.11g in 100 years, or in terms of velocity, a 1000 year return period of approximately 90 mm/s.
Moderate: 5 - 5.9
A moderate earthquake registers between 5 and 5.9 on the Richter scale and causes slight damage to buildings and other structures. There are about 500 of these around the globe every year.
No, earthquakes of magnitude 10 or larger cannot happen. The magnitude of an earthquake is related to the length of the fault on which it occurs.
Shallow earthquakes are between 0 and 70 km deep; intermediate earthquakes, 70 - 300 km deep; and deep earthquakes, 300 - 700 km deep.
In southeast Australia, the forces at the Pacific-Australian plate boundary to the east of us – the same plate boundary which passes through Aotearoa New Zealand – produce a buildup of strain. This is eventually released in the form of earthquake ruptures at weak zones or “faults” in the crust.
Australia is located centrally on the Australian plate, and is remarkably stable tectonically, with most of the coast classified as a passive margin or trailing edge.
Historical Tsunami
The largest Tsunami to have affected the NSW coast in recent times occurred in May 1960 after a 9.5 magnitude earthquake in Chile resulted in a 1 metre tidal fluctuation at Fort Denison in Sydney Harbour.
The earthquake of May 22, 1960, that struck the town of Valdivia in southern Chile is the most powerful ever recorded and has become known as the Great Chilean Earthquake. It is thought to have measured 9.5 on the moment magnitude scale (MMS).
The two largest recorded earthquakes in Queensland were Gladstone in 1918 with a magnitude of 6.3, and Gayndah in 1935 measuring a magnitude of 6.1.
"Sydney is more vulnerable, simply because there's more people, a lot close to the beach, and the density of construction." Cummins added that the north-western coast of Australia has experienced the most frequent tsunami waves in the past, but two factors minimise the impact.
A large tsunami affecting Australia is unlikely but possible. Remember that tsunamis are a sequence of waves that may occur over hours to days, and the biggest wave in the sequence could occur at any time.
In 1994 a tsunami travelled 300 metres inland in the Onslow-Exmouth region of WA. In 2006 a tsunami affected parts of the WA coast, particularly at Steep Point where a tsunami travelled 200 metres inland.