Researchers take a deep dive to alter earthquake data

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One of the largest earthquakes ever recorded in Australia shook Victoria in September, and researchers are now looking to the ocean depths before the next big earthquake.

Key points: Bass Strait seismograph will bring greater accuracy to future earthquake data Deployment of more seismometers could result in more earthquakes being recorded, experts acknowledge accurate earthquake predictions may never be available

The University of Melbourne operates a mostly ground network of more than 30 seismometers across Victoria, with the network detecting about 400 earthquakes each year in Gippsland alone.

More sites across the country are providing data to inform the search, using devices operated by Geoscience Australia and the School Outreach Programme.

But the ocean could be the next frontier.

A high-tech seismometer on the ocean floor, hidden under a yellow plastic sheet at the bottom of Bass Strait, collects and stores data on Earth’s movements.

It was published in early December, and it will remain at the sea floor to collect data until researchers return to collect it.

They will do this by sending a signal through the water to instruct the device to launch a buoy that floats to the surface to allow them to pull the seismometer on board.

Ocean floor seismometers extend university monitoring (ABC Gippsland: Peter Somerville)

That was when the hard work of University of Melbourne lead seismologist Januka Attanayake began.

“We collect a whole volume of data and look at the physics of earthquakes, particularly in blunt environments where this earthquake phenomenon is very mysterious,” said Dr. Atanayaki.

“We are trying to understand why these earthquakes happen and the physics behind these events.”

Why the ocean floor?

Expanding the network to the ocean floor expands the scope of the university’s monitoring.

“It was one of the largest earthquakes in Australian history in over 100 years and it was off Flinders Island,” said co-researcher Abraham Jones.

“You can’t install traditional instruments[outside]so the seismometers on the ocean floor really open up a larger part of the world to seismology.

“It really depends on where the earthquake is, but if there’s an earthquake very close to shore or far from shore, then these really come into play in terms of … being the nearest station.”

Abraham Jones and Januka Atanayaki checking a seismograph at Mount Beast (ABC Gippsland: Peter Somerville) It’s all about accuracy

A network of seismometers operated by Geoscience Australia across the country has a “reasonably dispersed network density”.

However, Mr Jones said the University of Melbourne’s network was more focused and designed to provide an accurate location for earthquakes, find faults and investigate in more detail.

Most university seismographs are ground-based. These sites are carefully selected and can transmit data to the university’s servers in real time.

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Mr. Jones said the deployment of more seismographs could also result in more earthquakes being recorded.

“Often having an instrument somewhere can identify and detect more earthquakes that people may not have known about because they were too small to feel.

“Australia is a huge country and we can’t cover every part of it, even on land, so if you have a remote desert land you might assume there are no earthquakes there, but if you turn off half a dozen instruments you might find some small tremors of one strength happen once in a while. for the last.

“This leads us to the question: Could this be a precursor to something else or an indication that an event occurred in the past?”

Abraham Jones with a seismometer installed at Mount Best in South Gippsland (ABC Gippsland: Peter Somerville) Questions remain

Dr Atanayake said earthquakes cannot be accurately predicted because “we don’t have the accuracy of measurements that can actually predict how [faults in the earth] They change.”

“Earthquakes are a very complex geophysical phenomenon,” he said. “There are two main factors that govern the occurrence of earthquakes.”

“One is the fault strength – what is the friction along the fault plane – and the other is the amount of stress that builds up on that fault level over time.

“These two components change over time, they are not very stable parameters.”

Abraham Jones and Januka Atanayaki prepare a seismometer for publication in Bass Strait (ABC Gippsland: Peter Somerville)

Mr. Jones said accurate earthquake prediction will likely never be available.

“We never know when stress builds up in a particular fault to reach that point of failure,” he said.

“There are a lot of fractures and fissures in the rock and a lot of other things that we don’t know about.

“You can’t analyze and model the pressure in all those different places to say, ‘Yeah, there’s going to be a lot of pressure here.'”

Space to play or pause, M to mute, left and right arrows to search, up and down arrows for volume. Watch Duration: 3 min 50 sec 3 m 50 s How big are the earthquakes in Australia and how prepared are we? .

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