Earthquake felt in Darwin was the biggest in over a decade

THE 7.2-magnitude earthquake that rocked Darwin yesterday was the biggest to hit the Banda Sea in more than a decade

Geoscience Australia senior duty seismologist Dean Connolly said today's earthquake was the largest to hit the area in 13 years since a 7.6 magnitude earthquake struck in 2006.

The largest quake recorded in the Banda Sea before that was a 8.2 in 1963.

"It was a very deep, over 207km deep, and the interesting thing about that is, if this earthquake was not as deep it would not have been felt as intensely in Australia," he said.

"There's a strange and rare phenomenon where earthquakes that happen in this part of the world have their energy channel southward, right towards the Northern Australia and the Top End.

"It happens in this sweet spot near the Banda Sea right where the plate boundaries are.

"When an earthquake hits deep there, the energy is directed in such a way that it's really pointed.

"That's why Darwin tends to feel a lot of these earthquakes, even though it's 700km away - which is a huge distance."

Chris Elders, a quake expert at Australia's Curtin University, said today's earthquake was a result of the relentless northward movement of Australia towards South East Asia.

"It is moving north at about 7.7cm per year, and part of the tectonic plate on which Australia sits has collided with Timor and Papua New Guinea," he said.

"The earthquake occurred at a depth of about 200km, and as the energy spreads upwards and outwards from the point at which it occurs, it will be felt in places as far away as Darwin."