As you noted, there are a lot of fringe operators in this field, and the term
seismo-electric and electro-seismic are often used interchangeably. ATS, whose
link you provided below, uses the term electroseismic for their
seismic-to-electrical method.
Both modes have big challenges: the loss of energy when converting EM to
seismic (motion) or vice versa is huge. This is demonstrated (indirectly) in
the article by Thomson et al in 2007 in The Leading Edge, when you look at the
size of the bank of 3-tonne, vibration-isolated, "power waveform synthesizers"
(i.e. generator/transmitters) needed for the method (Figure 6).
In seismo-electric there is the added problem that when you physically vibrate
an EM receiver you're going to get a signal. I suppose this is also likely
when you submit a geophone to a strong EM signal. Those cross-coupled signals
are at exactly the frequency you're looking for.
A key separator between mad science (type of voodoo) and real,
on-the-leading-edge research, is how the mad science types (and scammers)
over-simplify the technical problems in their set up and promises. The set up
in Thompson's paper clearly was not simple. But if a seller offers the same
results from a very simple field set up...
Greg Hodges
On Monday, September 23, 2019, 12:31:41 a.m. EDT, James Reid via SEGMIN
<[email protected]> wrote:
Hi All –
Having just discussed this post with Mike Asten, it seems I should issue a
clarification.
There are apparently both seismo-electric effects and electro-seismic effects.
I have been using the two terms interchangeably, but Mike informs me that they
are different things. The former uses a seismic source to generate an
electrical signal, and the latter conceptually uses an electrical source to
generate a seismic response.
In the report I had read, the field measurements were being done using a sledge
hammer source and measurements were being made of the resultant electric field,
so I should have referred to them as seismo-electric.
Thanks to Mike for pointing out the distinction.
Cheers,
James
From: SEGMIN <[email protected]>On Behalf Of James Reid via
SEGMIN
Sent: Monday, 23 September 2019 11:43 AM
To: [email protected]
Cc: James Reid <[email protected]>
Subject: [SEGMIN] Electro-seismics
This message originated outside Mira Geoscience.
Hi All –
I was wondering if anyone out there had any experience with electro-seismics,
i.e. using a seismic source to stimulate an electrical response from the ground.
I have recently had a groundwater contamination client request an
electro-seismic survey, with the objective of estimating the aquifer
permeability ahead of drilling. When I said that the method was pretty niche
and of academic interest in comparison with TEM, electrical resistivity
imaging or NMR, they said “but we’ve already done some”. When I read the
report I was underwhelmed to say the least… while I think there is some
physical basis to the technique (I recall genuine papers by Anton Kepic etc on
piezoelectric effects etc), the company in question were pseudoscientific at
best in terms of the data processing and interpretation, and their promises to
clients. The report had been commissioned (and accepted) by a very major
global geotechnical company who had clearly not employed a consultant
geophysicist.
There are several companies here in the Antipodes offering electro-seismic
surveys. These typically operate on the fringes of mainstream geophysics,
offering services to agriculture and groundwater. There is very little
information available on the physical basis of the method, or on its practical
limitations. Here is a link to one such company (chosen at random – I am not
picking on them because they are from New
Zealand)https://www.atsgeosuite.net/new-page. They have an intriguing sliding
price scale, where the client pays more for interpretation to larger depth – I
wish I had thought of that!
Anyway, I wondered whether anyone had any genuine experience with
electro-seismics, and could provide more detail. Is it a mature enough
technique that I should be considering it for hydrogeological work? I suspect
the answer is no, but I would be interested in any comments.
Cheers,
James
James Reid, Director Asia-Pacific, Principal Consultant
www.MiraGeoscience.com,tel +61.419 748 009, 45 Ventnor Ave, West Perth WA 6005
Australia
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