Earthquakes continue to hit Jamestown back-to-back

A total of 25 earthquakes have hit Jamestown this year with the latest occurrence on Wednesday morning.

A 1.8 magnitude earthquake hit at a depth of five kilometres and had 14 felt reports made, but last month a 4.2 magnitude earthquake rumbled the town causing damage to many properties.

Of the 25 total, there have been three earthquakes between a magnitude of three and four and 11 between a two and three magnitude.

Geoscience Australia senior seismologist Phil Cummins said generally SA has an elevated level of seismic activity.

"Those are mainly concentrated in Flinders Ranges, we don't usually get that many near Jamestown, but it's not actually that unusual to get smaller quakes near Jamestown," he said.

"The one that we had in April was large at 4.2, so that was unusually large.

"We've had about 25 this year near Jamestown, and that is somewhat high although you'd still get a few per year but they're usually smaller, so they're often not felt.

He said he noticed in 2011 there had a similar number, but they were small, so it was likely a lot more of them weren't felt.

"So it's not really as unusual as it might seem although it is higher than we've had in recent years," he said.

"Generally earthquakes in Australia because there's no tectonic plate boundaries in Australia, are caused by the gradual buildup of stress due to the forces transmitted from the plate boundaries in New Zealand, Papua New Guinea, and even as far away as India, and those stresses build up very slowly until they exceed the frictional strength of faults and then the faults rupture.

"We do get a bit more than elsewhere in Australia, and in that Flinders Ranges area, and that's probably associated with the fact that's one of the few places where we have active faults.

He said the range bounding faults trend North South "and some of those do seem to be active".

"And so that probably has something to do with the higher levels of seismicity," he said.

"I would say generally, it's unlikely (the tremors are building to a bigger one) but it's a possibility," he said.

"We can't discount it, as it is always possible that sequences of smaller earthquakes might be building to a larger earthquake, but it's more likely that they will simply die off over the next few months."

Jamestown local Kelly MacPherson said her house has been deemed unsafe to live in and has had to move out of town until it is repaired.

"Every room in our house has been damaged to the point where we're not able to live there at the moment," she said.

"Basically, every room around the cornice and in the corners of each room have been just completely displaced.

"It's like the roof did a dance that was different to the walls."

She was not home at the time the earthquake happened but had a friend looking after her daughter at home who described the tremor hitting the house "as though the roof lifted and shook".

"Then with every little tremor that has followed, the plaster has been falling off the wall," she said.

"So that's why it's unsafe for us to live there as well because the plaster basically de-laminated from the stone and brick work and so that's just sort of sitting loose and crazed.

"And then each time there's a tremor chunks fall off so every time we go into the house to check it, there is more debris on the floor."

Ms MacPherson said she had felt more than 10 of the tremors but hadn't felt any since moving to Mannanarie.

"If anything, that's a good thing because my daughter, Isla, (who is six) was quite traumatised so for her to be out of the town is actually a blessing," she said.

"It was getting to the point where she wasn't letting go of me at all - she literally watched her room break apart."

She said they were fortunate enough to be fully insured and covered from the earthquake damage.

"It's inside and outside, where basically the whole house will need to be replastered, repainted and patched on the outside; and then repainted and then potentially pins put in the sandstone walls," she said.

"I'm not sure how they fix the alignment of the cornice to the wall, but that'll need to be done as well.

"Every single room has been destroyed."

Despite the damages Ms MacPherson is remaining positive and said everything happens in cycles so it's likely a reoccurring event which wasn't well documented the last time a burst of earthquakes happened.

"Everyone likes to blame someone for something," she said.

"It's just been a really unfortunate series of events that I'm glad it's happened to us rather than anyone else, because we can handle it.

"But we have been inundated with meals and well wishes and offers of help - which has been really lovely."

She said it would be really good to have some form of reassurance for the community whether it is through a town meeting, a Q&A or a public announcement of information.

"We need something where people can actually put their minds at ease because there's lots of older people that are very nervous and they really don't have to be," she said.

"From what I have heard they just want someone to tell them that it's all going to be okay."

A separate Facebook page has been made called Jamestown Earthquakes as many members of the community were posting concerns or looking for support and information.

One member of the group wrote "It's starting to be... Was that another earthquake? A big truck? A train? It's very unnerving not knowing if we've had the "Big One" or is it just brewing. Slightest rumble puts me on edge now," the post read.

After the earthquake on Tuesday, a post within the Jamestown Community Notice Board group on Facebook was made with a reply of "getting scary, do we sell and move?".

Northern Areas Council chief executive officer Kelly Westell said several council owned buildings, including the Jamestown office, "sustained minor damage - mostly cracking - after the initial quake and some of the cracks have opened up a little more in the past week".

"This will be assessed by our insurers in due course," she said.

"Like most locals, we are finding the daily jolts annoying but these are relatively minor and short-lived.

"The community is taking these rumbles in its stride - we have been speaking to a number of community members and will undertake broader engagement if we believe it's necessary.

"(But) at this stage there doesn't appear to be high anxiety, just a sense we'd like things to settle now."