When is the next big one?

Earthquakes are a sudden phenomenon. Therefore, seismologists have no way of knowing exactly when or where the next one will hit.

"I can't tell you when the next earthquake is going to happen," Mr Maldoni said. "But I can tell you it's going to happen along a fault line."

Which fault line however, is anyone's guess.

"Normally what happens is, you have an initial earthquake and you tend to get a series of aftershocks, but sometimes you don't. Or sometimes, that initial earthquake can be a foreshock to another earthquake," Mr Maldoni said. "But the probability of a large earthquake is very, very small."

He said it was unlikely Thursday's Pakenham earthquake was related to the quake which hit the Gippsland town of Korumburra on Wednesday morning.

"They are sufficiently far apart that I do not think they are related. You're not likely to get much [activity] more after today's event," he said.

Are we safe?

It would take a "very, very large earthquake" - a magnitude of 6.5 at least - in the Gippsland area to have a major, destructive impact on Melbourne, seismologists say. The level of damage depends on what is in the vicinity of the earthquake's epicentre.

A 5.4 magnitude earthquake which hit near the town of Moe in 2012 caused about $20 million damage and was felt across Melbourne. Fortunately, many of Victoria's earthquakes measure less than 3.5, causing very little damage.

Minimum building standards for earthquakes first applied in Victoria in 1994, but Matthew O'Hearn of Engineers Australia has told Fairfax Media it was unlikely a large number of buildings in Melbourne would "topple over" in an earthquake.

Are earthquakes common in Victoria?

Yes. Last year alone, 13 earthquakes with a magnitude of 2.5 or more were recorded in Victoria by the Seismology Research Centre. However, it is likely there were many more which would have been too weak to be detected.

Over the past 114 years, about 1800 earthquakes have been detected across the state, the majority of which were recorded in the Gippsland area.

What happens?

Australia sits in the middle of a tectonic plate known as the Indo-Australian plate which is moving in a north-east direction. The movement of the plate creates a build-up of pressure in the earth's crust. That pressure needs to be released and often escapes along Victoria's minor fault lines, resulting in an earthquake. These earthquakes are known as "intraplate" quakes.

A number of fault planes have been identified in Victoria, including the Strzelecki Ranges, the Mornington Peninsula and the Otway Ranges. Thursday morning's earthquake near the eastern suburb of Pakenham shows that there may be a number of minor fault lines in the local area.

Why Victoria?

In short, the reason lies in Victoria's mountainous landscape. The state's Strzelecki and Otway ranges indicate that the Earth's crust has already undergone a lot of stress, creating weak fault lines. "Fault lines that are very much still active," Mr Maldoni said.

When is a tremor an earthquake?

The answer is, almost always. By definition, an earthquake is an earth tremor.

"When we say earthquake we actually mean a natural earth tremor, as opposed to a tremor caused by a man-made event," Geoscience Australia seismologist Marco Maldoni said.

Recent earthquakes

The Thursday, December 4, 3.2 magnitude quake struck about five kilometres south of the suburb of Pakenham.

On Wednesday, a 3.3 magnitude quake was felt in the Gippsland town of Korumburra, but no damage was reported.

On 19 June 2012, a magnitude 5.4 earthquake occurred in the state's southeast at 8:53pm. The earthquake epicentre was 16 kilometres south-west of Moe and was the strongest quake recorded since the 1982 and was felt across the state including in Melbourne and as far away as Wodonga.

In August 2000, a magnitude 5.0 in Boolarra caused minor damage and was felt throughout Gippsland and in 2009, Korumburra experienced two earthquakes within two weeks of each other on the 6 March and then the 18 March. Both earthquakes were recorded at a magnitude 4.6.

On Wednesday, a 3.3 magnitude quake was felt in the Gippsland town of Korumburra, but no damage was reported.

Severe earthquakes

Australia's most severe earthquake occurred in Newcastle in 1989 when a 5.6 magnitude quake killed 13 people and caused billions of dollars in damage.

In comparison, a 6.3 earthquake with a shallow epicentre struck 10 kilometres south-east of Christchurch on New Zealand's South Island in February 2011, turning much of the city centre to rubble and killing 181 people, while a huge, magnitude 9.0 quake (possibly the fourth most powerful ever recorded) struck off the coast of Japan creating a tsunami that killed 25,000 people, wiped entire towns off the map, and caused one of the largest nuclear disasters in history.

Can animals predict earthquakes?

This question is often asked. But precisely what animals sense, if they sense anything at all, is a mystery.

One theory is that wild and domestic animals feel the earth vibrate before humans do. It has also been suggested that animals can detect electrical changes in the air. As for sensing an impending earthquake days or weeks before it occurs, that's a different story. "We would need to do a very thorough scientific study to determine that," Mr Maldoni said.

Australia's tectonic plate

Most of the world's earthquakes happen along the boundaries of the planet's tectonic plates, with about 80 per cent occurring around the edge of the Pacific Plate (the "Rim of Fire"), affecting New Zealand, Japan and the west coast of North and South America.

Australia does not sit on the edge of a tectonic plate, lying instead in the middle of the Indo-Australian plate. Australia shares its tectonic plate with India and part of New Zealand. The Australian plate is the earth's fastest-moving continental plate and is being pushed to the north-east at a rate of about seven centimetres per year. It is colliding with the Eurasian, Philippine and Pacific Plates, causing stress to build up in the 25-kilometre-thick upper crust.