Those were good questions Sergio, can't say I remember seeing a ground contractor 3D gradiometer array system using scalar or vector magnetometers either, a 3D vector one would effectively be a ground mag tensor gradiometer that returned 12 vector components, a wealth of data, and perhaps would look like a smaller version of that heli-triaxial system posted up on the other gradiometer thread,
Red Rocks has a standard GSMP35 scalar ground gradiometer available when it's not being used, much less sophisticated than the multi-sensor airborne systems shown on the threads, that does a simple 1D two-sensor array, either horizontal or vertical, Cheers, Ed mobile/text 001-720-300-3641 Sent from my T-Mobile Android device On Wed, May 8, 2019 at 11:52 AM S E Geoscience and Exploration via SEGMIN < [email protected]> wrote: > Thank you everyone to all your comments. > > I just want to keep it simple. Instead of calculating the gradients (e.g. > 1stVD, 1stHD in EW, etc.) using any available software, I would like to > measure it. I am interested in the total magnetic field intensity as a > scalar, hence in just the strength of the total field, not in its > direction. However RtP transformations are always preferred. So, the > inclination should be 90 degrees. > > So, grad TMI, nabla TMI, partial d TMI / partial d space, etc. is my > interest. This can be approximated by two simultaneous (or almost > simultaneous) measurements of TMI and by a set distance. I have > tried single gradients in airborne and ground platforms, with VTEM as > offered by Geotech (horizontal gradient perpendicular to flight direction) > and by GEM Systems (vertical gradient measured with two GSM-19). > > Results are always impressive. Besides improving S/N, it delivers measured > gradients, not calculated ones. The horizontal gradient worked very well > e.g. in a known porphyry near Copiapo, Chile. We were about to rename the > porphyry to Donut, because of the shape of the gradient and the exact > mapping of contacts. It works well with other geological geometries. > > I was wondering who was offering a full gradient system on a ground > platform. I already have the answer. > > By the way, I have nothing to do with the search of the missed aircraft. > > Regards > > > > On Fri, May 3, 2019 at 11:59 AM Ed Cunion via SEGMIN < > [email protected]> wrote: > >> The 2 cents understanding here while having lunch, >> >> Having been involved on surveys using triaxial airborne gradiometer and >> 3-axis fluxgate vector magnetometers- >> >> Measured gradiometer surveys usually use scalar sensors -alkali vapor- >> etc. to measure the difference between cross-axis sensors, cross wing, >> cross tail, cross fuselage, say for a fixed wing. The sensors measure the >> scalar total field. The gradient across the scalar sensors is then >> determined. >> >> Fluxgates, the 3-axis type, Bartington is one manufacturer, there are >> several even chip scale now, alternatively, measure the three vectors of >> the magnetic field and return the three vector readings. The fluxgate can >> either be aligned in some way with the 3D earth field, say like might be >> seen at an observatory like in Boulder, or not, like out on some sort of >> field survey for example, UXO, Archeology, whatever, why limit yourself? As >> the fluxgate provides the 3D vectors, a bonus is these can be combined to >> get a total field reading too. >> >> Taking this one step further, vector magnetometers can be used instead of >> scalars, in 2D or 3D gradient arrays. As might be expected this produces a >> wealth of magnetic field data to process and interpret. >> >> Fluxgates can also be used in EM, Smartems been around for a while, MT >> too? >> >> Cheers, >> >> Ed >> >> Red Rocks Geophysical >> Mobile 001 720 300 3641 >> >> Sent from my T-Mobile Android device >> >> >> >> On Fri, May 3, 2019, 8:44 AM S E Geoscience and Exploration via SEGMIN < >> [email protected]> wrote: >> >>> Joel, >>> >>> can you please expand on that ("the gradient of the total field is not >>> the same as the gradient of the field")? >>> >>> A gradient is a spatial derivative, changes of a value in space. So, >>> what is the difference between the value "(magnetic) total field" and the >>> value "(magnetic) field"? >>> >>> Thanks >>> >>> >>> On Thu, May 2, 2019 at 10:08 AM Jansen, Joel via SEGMIN < >>> [email protected]> wrote: >>> >>>> Peter has brought up a good point: that the gradient of the total >>>> field is not the same as the gradient of the field. The former can be >>>> collected with proton or Cs/K-vapour magnetometers, while the latter >>>> requires fluxgates or SQUIDS. >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> * Joel Jansen D +1 604 696 3511 M +1 604 218 3887 From: >>>> SEGMIN <[email protected] >>>> <[email protected]>> On Behalf Of Peter Annan via SEGMIN >>>> Sent: May 1, 2019 7:52 PM To: [email protected] >>>> <[email protected]> Cc: Peter Annan <[email protected] >>>> <[email protected]>> Subject: Re: [SEGMIN] full gradient mag surveys This >>>> message originated outside Anglo American ------------------------------ >>>> Hi Richard: From my understanding and talking to many in the archeo >>>> field, these are primarily single axis gradiometers or arrays of these >>>> devices and not triaxial gradiometers. Someone may have a more advanced >>>> version since there are lot of people playing but have not see a triaxial >>>> unit. More likely to find the triaxial solution in the UXO area if there >>>> is one.. Regards Peter From: SEGMIN <[email protected] >>>> <[email protected]>> On Behalf Of Richard Smith via SEGMIN >>>> Sent: Wednesday, May 1, 2019 10:33 PM To: [email protected] >>>> <[email protected]> Cc: Richard Smith <[email protected] >>>> <[email protected]>> Subject: Re: [SEGMIN] full gradient mag surveys >>>> There are lots of archeological groups doing multisensory mag for Greek and >>>> Roman ruins, Stonehenge etc. There was someone from Flinders University in >>>> South Australia written up recently in Preview. These systems are >>>> generally towed by a quadbike or similar and are designed for open spaces >>>> like fields. Regards Richard Smith -----Original Message----- From: >>>> Roger Henderson via SEGMIN <[email protected] >>>> <[email protected]>> To: segmin <[email protected] >>>> <[email protected]>> Cc: Roger Henderson <[email protected] >>>> <[email protected]>> Sent: Wed, May 1, 2019 8:07 pm Subject: Re: [SEGMIN] >>>> full gradient mag surveys Yes, Sergio did say GROUND and he gets offered >>>> helicopter systems. Hasn’t any one watched the British TV show “Time team” >>>> using triaxial mags for archaeology? I think they were fluxgates made by >>>> Bartington. Anyway plenty of others . Geometrics? Peter Annan Chief >>>> Executive Officer Sensors & Software Inc. 1040 Stacey Court, Mississauga, >>>> Ontario, Canada L4W 2X8 [email protected] <[email protected]> | +1 905 624 >>>> 8909 >>>> www.sensoft.ca <http://www.sensoft.ca/index.html> This transmission may >>>> contain PRIVILEGED OR CONFIDENTIAL INFORMATION. Unauthorized disclosure is >>>> strictly prohibited. On 2 May 2019, at 5:17 am, Stephen Reford via >>>> SEGMIN <[email protected] <[email protected]>> wrote: Here >>>> is another one: http://www.shageophysics.com/heli-gt.html >>>> <http://www.shageophysics.com/heli-gt.html> No doubt there are a few >>>> other heliborne triaxial gradiometers out there. However, I see that >>>> Sergio is asking for a ground triaxial gradiometer. From: SEGMIN >>>> <[email protected] <[email protected]>> On >>>> Behalf Of Pierre Bérubé via SEGMIN Sent: May 1, 2019 3:12 PM >>>> To: [email protected] <[email protected]> Cc: Pierre Bérubé >>>> <[email protected] <[email protected]>> Subject: Re: [SEGMIN] >>>> full gradient mag surveys Never had any problems with these guys, they >>>> should be able to deliver what you want. >>>> https://www.facebook.com/Airborne-Geophysics-Eagle-K8aranda-Geophysics-133062360111477/about/ >>>> <https://www.facebook.com/Airborne-Geophysics-Eagle-K8aranda-Geophysics-133062360111477/about/> >>>> Pierre <image001.jpg> Pierre Bérubé, ing. / Eng. Président / >>>> President _______________________________________________ >>>> tel.: 1.819.874.8800 #201 fax: 1.819.874.8801 1740 chemin >>>> Sullivan suite 1400, Val-d’Or (QC) Canada J9P 7H1 www.ageophysics.com >>>> <http://www.ageophysics.com/> <image002.jpg> From: SEGMIN >>>> <[email protected] <[email protected]>> On >>>> Behalf Of S E Geoscience and Exploration via SEGMIN Sent: May 1, 2019 9:12 >>>> AM To: [email protected] <[email protected]> Cc: S E >>>> Geoscience and Exploration <[email protected] >>>> <[email protected]>> Subject: [SEGMIN] full gradient >>>> mag surveys Dear all, is there a ground geophysical contractor offering >>>> full gradient mag surveys? (horizontal gradient perpendicular to profile >>>> direction + vertical gradient). Thanks -- Sergio Espinosa, Ph.D., >>>> P.Geo Director, Geophysics S E Geoscience & Exploration >>>> ----------------------- SEGMIN community mailing list service >>>> ([email protected] <[email protected]>). Change your personal >>>> options >>>> here: https://lists.geosoft.com/mailman/options/segmin/rogah%40tpg.com.au >>>> <https://lists.geosoft.com/mailman/options/segmin/rogah%40tpg.com.au> >>>> Colleagues can join here: https://lists.geosoft.com/mailman/listinfo/segmin >>>> <https://lists.geosoft.com/mailman/listinfo/segmin> >>>> Archives: https://lists.geosoft.com/mailman/private/segmin/ >>>> <https://lists.geosoft.com/mailman/private/segmin/> NOTE that <Reply> will >>>> reply to all members of the list. ----------------------- SEGMIN >>>> community mailing list service ([email protected] >>>> <[email protected]>). 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Change your personal >>>> options here: >>>> https://lists.geosoft.com/mailman/options/segmin/se.geoscience.and.exploration%40gmail.com >>>> <https://lists.geosoft.com/mailman/options/segmin/se.geoscience.and.exploration%40gmail.com> >>>> Colleagues can join here: https://lists.geosoft.com/mailman/listinfo/segmin >>>> <https://lists.geosoft.com/mailman/listinfo/segmin> Archives: >>>> https://lists.geosoft.com/mailman/private/segmin/ >>>> <https://lists.geosoft.com/mailman/private/segmin/> NOTE that <Reply> will >>>> reply to all members of the list. * >>> >>> >>> >>> >>> *-- Sergio Espinosa, Ph.D., P.GeoDirector, GeophysicsS E Geoscience >>> & Exploration* >>> >>> >>> >>> >>> >>> >>> * ----------------------- SEGMIN community mailing list service >>> ([email protected] <[email protected]>). Change your personal >>> options here: >>> https://lists.geosoft.com/mailman/options/segmin/ed.cunion%40gmail.com >>> <https://lists.geosoft.com/mailman/options/segmin/ed.cunion%40gmail.com> >>> Colleagues can join here: https://lists.geosoft.com/mailman/listinfo/segmin >>> <https://lists.geosoft.com/mailman/listinfo/segmin> Archives: >>> https://lists.geosoft.com/mailman/private/segmin/ >>> <https://lists.geosoft.com/mailman/private/segmin/> NOTE that <Reply> will >>> reply to all members of the list. * >> >> >> >> >> >> >> >> * ----------------------- SEGMIN community mailing list service >> ([email protected] <[email protected]>). Change your personal >> options here: >> https://lists.geosoft.com/mailman/options/segmin/se.geoscience.and.exploration%40gmail.com >> <https://lists.geosoft.com/mailman/options/segmin/se.geoscience.and.exploration%40gmail.com> >> Colleagues can join here: https://lists.geosoft.com/mailman/listinfo/segmin >> <https://lists.geosoft.com/mailman/listinfo/segmin> Archives: >> https://lists.geosoft.com/mailman/private/segmin/ >> <https://lists.geosoft.com/mailman/private/segmin/> NOTE that <Reply> will >> reply to all members of the list. * > > > > > *-- Sergio Espinosa, Ph.D., P.GeoDirector, GeophysicsS E Geoscience > & Exploration* ----------------------- > SEGMIN community mailing list service ([email protected]). > Change your personal options here: > https://lists.geosoft.com/mailman/options/segmin/ed.cunion%40gmail.com > Colleagues can join here: > https://lists.geosoft.com/mailman/listinfo/segmin > Archives: https://lists.geosoft.com/mailman/private/segmin/ > NOTE that <Reply> will reply to all members of the list. >
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