Henry, it is definitely not a trick. Those orthogonal gradients are intertwined more than we think. The explanation is to be found in Potential Theory.
Regards On Wed, Oct 7, 2020 at 4:03 PM Henry Lyatsky via SEGMIN < [email protected]> wrote: > Personally, I am no fan of tricks that combine such dissimilar beasts as > vertical and horizontal derivatives. Math is abstract and it can bear > anything, but we should remain skeptical when it comes to mixing apples and > oranges. For this reason, I also dislike the total gradient (analytic > signal). > > The mathematically simplest methods are best, combined with solid > geological thinking. > > *Henry.........................................................* > *Dr. Henry Lyatsky, P.Geoph., P.Geol.* > *cell: 403/710-7490 [email protected] <[email protected]>* > *Skype: henry.lyatsky* > *www.linkedin.com/in/lyatsky/* <https://www.linkedin.com/in/lyatsky/> > > *This message and any attachments are confidential. Any redistribution > is strictly prohibited. If you are not an intended recipient, please > notify the sender and delete this message and attachments from your > system. Please check this message, links and attachments for viruses; we > accept no liability for any malware damage. Thank you.* > > ------------------------------ > *From:* SEGMIN <[email protected]> on behalf of S E > Geoscience and Exploration via SEGMIN <[email protected]> > *Sent:* Wednesday, October 7, 2020 1:43 PM > *To:* [email protected] <[email protected]> > *Cc:* S E Geoscience and Exploration < > [email protected]> > *Subject:* Re: [SEGMIN] Tilt is not a derivative > > Alan > > thank you for the comments. > > My point is that the term "Tilt Derivative" might be rather confusing for > non geophysicists, since they might tend to think that it is a derivative, > or a change of a parameter Y (e.g. Magnetic Induction B) in relation to > parameter X (e.g., Depth Z or Time t), which is not. > > "Derivative Tilt" is certainly more appropriate. When I explain the useful > parameter to the geoscientist who is not knowledgeable in potential > techniques, I tell them that it is a sort of "amplitude equalizer" in order > to enhance weaker and low frequency signals in order to see better in areas > with thick cover, so that they understand. > > Generally, I personally prefer to use the term "Gradient" instead of > "Derivative", for obvious reasons. But I understand that technical jargon > is deeply rooted. > > Thanks > > > > On Wed, Oct 7, 2020 at 11:47 AM Alan Reid via SEGMIN < > [email protected]> wrote: > > Folks, > > There’s a clear enough definition in the paper by Verduzco et al in The > Meter Reader (TLE February 2004). I believe they coined the term, so their > definition should stand. TDR (Tilt Derivative) is effectively the tilt of > the derivatives, They also define the “TDR_THDR” which is the total > horizontal derivative of the TDR. I do not believe Verduzco et al were > trying to suggest that Tilt is a derivative. Its clearly not. > > Given that they defined and published the term, perhaps we should respect > that and not go off with our own names for this entity? Nor go off with > other definitions for the term? > > I confess that “Derivative Tilt” might have been a more descriptive name, > but it somehow doesn’t have much of a ring, does it? Anyway, its useful as > described. And I teach it and use it in that form. > > I do not have any conflict of interest to declare, here. > > Regards > > Alan Reid > > On 6 Oct 2020, at 18:40, S E Geoscience and Exploration via SEGMIN < > [email protected]> wrote: > > Thanks. > > I prefer to call it "Amplitude Equalizer", sort of. > > On Tue, Oct 6, 2020 at 1:35 PM Richard Smith via SEGMIN < > [email protected]> wrote: > > Perhaps it is called tilt derivative as you have to calculate derivatives > to calculate it, as in the "tilt of the derivatives". Personally, I > prefer the term, "local phase" (Thurston and Smith, 1997), but I have a > conflict of interest! > > Regards > Richard Smith > > > > -----Original Message----- > From: S E Geoscience and Exploration via SEGMIN <[email protected]> > To: [email protected] > Cc: S E Geoscience and Exploration < > [email protected]> > Sent: Tue, Oct 6, 2020 11:29 am > Subject: [SEGMIN] Tilt is not a derivative > > Dear all, > > I am always so puzzled. Why do people call the Tilt in potential > techniques a derivative? It is not. > > Regards > > -- > *Sergio Espinosa, Ph.D., P.Geo* > Director, Geophysics > *S E G*eoscience & *Ex*ploration > ----------------------- > SEGMIN community mailing list service ([email protected]). > Change your personal options here: > https://lists.geosoft.com/mailman/options/segmin/geofizzics%40aol.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. > ----------------------- > SEGMIN community mailing list service ([email protected]). > Change your personal options here: > https://lists.geosoft.com/mailman/options/segmin/se.geoscience.and.exploration%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. > > > > -- > *Sergio Espinosa, Ph.D., P.Geo* > Director, Geophysics > *S E G*eoscience & *Ex*ploration > ----------------------- > SEGMIN community mailing list service ([email protected]). > Change your personal options here: > https://lists.geosoft.com/mailman/options/segmin/alan%40reid-geophys.co.uk > 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. > > > Alan B Reid PhD > Reid Geophysics Ltd > 7 Keymer House > Michel Grove > Eastbourne BN21 1JZ > UK > > Phone: +44 (0) 1323 735520 > Mobile: +44 (0) 781 692 4728 > Skype Name: alanbarryreid > mailto: [email protected] > web: http://www.reid-geophys.co.uk > > > ----------------------- > SEGMIN community mailing list service ([email protected]). > Change your personal options here: > https://lists.geosoft.com/mailman/options/segmin/se.geoscience.and.exploration%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. > > > > -- > *Sergio Espinosa, Ph.D., P.Geo* > Director, Geophysics > *S E G*eoscience & *Ex*ploration > ----------------------- > SEGMIN community mailing list service ([email protected]). > Change your personal options here: > https://lists.geosoft.com/mailman/options/segmin/se.geoscience.and.exploration%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. > -- *Sergio Espinosa, Ph.D., P.Geo* Director, Geophysics *S E G*eoscience & *Ex*ploration
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