27 March, 2014 9:07AM AEDT

Scientists on lookout for volcanic rock on Tasmania's east coast

The school of earth science at the University of Tasmania is asking people on the east coast of the state to be on the lookout for the volcanic rock, pumice as it washes up on our shores.

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"In 2012 there was a fairly large explosive sub-marine eruption. About 1000 kilometres north of Auckland, New Zealand in about 700 metres depth of water," says Dr Rebecca Carey from the school of earth science with the University of Tasmania.

For people who aren't too sure exactly what pumice is, Dr Carey explains 'it's basically a volcanic product and it's very porous, has a density less than water so it can float on the ocean surface for years, potentially decades.'

According to Dr Carey the pumice is most likely going to be quite hard and probably round and by the time it hits Tasmanian shores and will also have quite a lot of biological cargo attached.

"There's been reports of some pumice arriving with up to 80 different marine species. So it could be white brown or black coloured.

"It's probably going to have a lot of biology on it, basically hitchhikers that have come for a ride to Tasmania," she says.

Because the underwater eruption was quite explosive, pumice was blasted to the surface of the ocean and Dr Carey estimates it could be about a cubic kilometre worth of the volcanic rock.

"In 2012 we were able to detect that eruption because of satellite imagery and then pretty much two weeks after that eruption, the pumice began to arrive on New Zealand beaches.

"Subsequent to that we tracked it in Fiji and Tonga and about this time last year it made its way to Queensland," she explains.

Now that the very light weight rock has been spotted on north east Tasmanian beaches, Dr Carey is keen to hear from members of the public who might find pumice.

"We're trying to get the communities assistance in terms of putting this jigsaw puzzle together and how fast it's propagating down the east coast of Tasmania.

Dr Carey says the size may vary but because the rock has already had quite a journey through the ocean since 2012, it's most likely going to be quite small.

"On the mainland we were getting reports up to basketball size. So potentially by now we should be expecting maybe smaller sizes," she says.

The critical points for the University are the location and the time the pumice was found. Also a photograph even just taken on a smart phone, up-close to show any marine species that may have attached themselves to the volcanic rock.

Dr Rebecca Carey can be contacted through the University of Tasmania