Recent earthquakes in Far South West Queensland/Far North East South Australia
turnb...@gmail.com
Hi Everyone.
On 2021-09-04 05:15 (UTC) an ML 2.7 earthquake occurred 30 km NW of Innamincka in the far NW of South Australia.
21 hours later, on 2021-09-05 12:07 (UTC) an ML 2.9 earthquake occurred 100 km SW of Thargominda in far SW Queensland (20 km N of an ML 3.2 that occurred on 2017-01.22 15:34 UTC) about 250 km SE of Innamincka.
The latter two events mentioned above clearly indicate a seismogenic zone on Bulloo Downs station (just 10 km south of the nearest event); and the Innamincka event probably indicates similar seismicity in the Innamincka area. Common thinking would suggest that these two seismogenic areas are mutually exclusive – HOWEVER, the occurrence of ML ~3 events in this remote region is so rare (well … not “rare” but certainly only one every 5 years or so) that the occurrence of two such events within hours of one-another (even though they are 250 km apart) suggests the possibility that the two seismic zones may be linked in some way cannot be ignored and suggests the need for further focused research.
What a great pity that the responsible authorities in Australia, Queensland, and South Australia do not have sufficient resources nor the scientific interest to perform adequate monitoring of these remote regions to give us some further insight into the true seismicity and seismogenic relationships of these regions – keeping in mind that these regions are actively being mined for deep natural gas and other petrofuels, and feasibility studies of shallow gasification of sub-economic coal seams in the broader regions has already started and WILL extend into the areas in which these recent earthquakes occurred within 50 years or less.
Regards
Michael Lloyd Turnbull BAppSc(Distinction) QUT, MAppSc CQU.
Lead Seismologist, Central Queensland Seismology Research Group (CQSRG).
Adjunct Research Fellow, CQUniversity Australia (CQU).
Member of the Australian Earthquake Engineering Society (Since 1997).
Foundation Member of the Seismological Association of Australian (SAA)
Retired Member of the Australian National Committee on Large Dams (ANCOLD)
Member of the Royal Society of Queensland
619 Horsecamp Road
Horse Camp, Qld. 4671
Telephone: (07) 41576538
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Dan
There is certainly a lot to discover in this area. Mike sandiford and colleagues have recently published on tectonic modification of aquifers in the Great artesian Basin:
Sandiford, M., Lawrie, K. & Brodie, R.S. Hydrogeological implications of active tectonics in the Great Artesian Basin, Australia. Hydrogeol J 28, 57–73 (2020). https://doi.org/10.1007/s10040-019-02046-4
Cheerio,
Dan.
Mike Turnbull
Cheers Dan & all
Thanks for that. I’ve been on Google looking for Cooper Basin HFR/HDR references. What I am finding is that the HFR activity is induced below the Great Artesian Basin aquifers (about 2000 m below the GAB), and that the fracturing does not penetrate above as far as the aquifer levels – is that correct? However, since the GFR bore wells transect the GAB aquifer levels, there is a need to seal the bore holes at those levels. There is some discussion (although I’m not finding it in any academic papers) that the bore hole sealing is being done using bentonite rather than concrete and that the hydraulic pressure is displacing the seal such that “gas” is intruding into the aquifers. I would have thought that with HFR, if any aquifer intrusion were to occur, it would be the down-going hydraulic water or the returning steam rather than “gas”.
Does anyone have any knowledge of this, or an opinion?
Cheers
Mike Turnbull
From: aee...@googlegroups.com <aee...@googlegroups.com> On Behalf Of Dan
Sent: Monday, 13 September 2021 4:07 PM
To: aeesorg <aee...@googlegroups.com>
Subject: [aees] Re: Recent earthquakes in Far South West Queensland/Far North East South Australia
Hi Mike,
There is certainly a lot to discover in this area. Mike sandiford and colleagues have recently published on tectonic modification of aquifers in the Great artesian Basin:
Sandiford, M., Lawrie, K. & Brodie, R.S. Hydrogeological implications of active tectonics in the Great Artesian Basin, Australia. Hydrogeol J 28, 57–73 (2020). https://doi.org/10.1007/s10040-019-02046-4
Download link: https://rdcu.be/cxDPd (i think the article is open access - if not, let me know and i can post a preprint)
The story is of a series of blind reverse faults propagating into the Cenozoic basin sediments, and manifesting as broad warps and folds at the surface. Because it is so flat, there is a marked effect on the river systems. The most recognisable is the Innamincka Dome.
Cheerio,
Dan.
On Monday, September 6, 2021 at 11:27:13 AM UTC+10 turnb...@gmail.com wrote:
Hi Everyone.
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