Do we need to worry about recent earthquakes across the Asia Pacific?

Myanmar's catastrophic earthquake last month came amid a flurry of smaller earthquakes across the Asia Pacific.

The magnitude-7.7 quake near Mandalay on March 28 left more than 3,600 people dead and shook the Thai capital of Bangkok, more than 1,000 kilometres away.

Days before that on March 25, a magnitude-6.7 earthquake hit off New Zealand's South Island.

On April 2, Japan was hit with a magnitude-6 quake, on April 4, a magnitude-7 earthquake struck Tonga, and on April 5 Papua New Guinea felt another magnitude-6.9 quake.

Yesterday, Taiwan was hit by a magnitude-5.8 quake.

None of these smaller quakes resulted in deaths or significant damage.

But how unusual is it to have a cluster of quakes like this, and do people in the Asia Pacific need to be worried?

We spoke to seismologists to find out.

'Within the normal range'

Brian Kennett is emeritus professor of seismology at the Australian National University's Research School of Earth Sciences.

He said earthquakes often arrived in bunches.

It was understandable that people might be concerned, he said, because there had been quite a few recently over a short span of time.

However, he said they were mostly "within the range you would expect".

"The Myanmar quake was an outlier because it's in a much more infrequent class.

Dee Ninis, an earthquake geologist at the Seismology Research Centre in Melbourne, similarly said there was no cause for concern, and that the large number of quakes so close together was a coincidence.

"On average across the globe we see about 18 major earthquakes — magnitude-7 to 7.9 — every year," she said.

"But these earthquakes are not equally spaced out over any period of time; they often tend to cluster just as a result of their randomness," she said.

Dr Ninis said earthquakes were caused by a "build-up and sudden release of stress in the earth's crust".

"Larger-sized earthquakes often produce aftershocks — an increase in earthquake activity which can last for days, weeks, months, or years afterwards," Dr Ninis said.

But the quakes across the Asia Pacific were too distant from each other to be aftershocks of the Myanmar quake, she said.

Although the recent earthquakes fell along the India-Australia plate boundary, Dr Ninis said they were likely unrelated, "responding to local plate boundary tectonic forces generating stress within the crust "

"When there is pressure built up in the crust, even a large earthquake may not be enough to release it," she said.

The pressure would then find a weak point somewhere else to burst through, but pinpointing where that had happened was difficult.

What about Australia?

Australia also felt some tremors during this period.

The New South Wales-Victoria border town of Albury was shaken by a magnitude-3.7 quake on April 4.

Dr Ninis said this one, too, was completely normal.

"We typically experience 30-40 earthquakes per week [in south-east Australia], and maybe 15-20 of magnitude-3 to 3.9 every year," she said.

So, while Australia can be impacted by the same tectonic movements and pressure build-up that cause earthquakes further north, the effect is muted.

As for being able to predict them better, Dr Kennett and Dr Ninis say the science is improving, but "forecasting" is a better word.

"Forecasts detail the likelihood of a certain magnitude earthquake, in a certain location, over a certain time period. Forecasts can change," Dr Ninis said.

"There is an approximately 80 per cent chance that this will be a great earthquake, a magnitude-8.0 or above," she said.

In Japan, there's a long-standing forecast of a magnitude-9 "mega-quake" hitting off its Pacific coast within the next 30 years.

The Japanese government has recently revised its damage estimate from such an event to over $US1.8 trillion ($3 trillion).

Seismologists are improving rapidly in terms of forecasting ability, but Dr Kennett said advancements are only useful if the information is put into practice.