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] 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]<mailto:[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]<mailto:[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]<mailto:[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]<mailto:[email protected]>> To: [email protected]<mailto:[email protected]> Cc: S E Geoscience and Exploration <[email protected]<mailto:[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 Geoscience & Exploration ----------------------- SEGMIN community mailing list service ([email protected]<mailto:[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]<mailto:[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 Geoscience & Exploration ----------------------- SEGMIN community mailing list service ([email protected]<mailto:[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]<mailto:[email protected]> web: http://www.reid-geophys.co.uk ----------------------- SEGMIN community mailing list service ([email protected]<mailto:[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 Geoscience & Exploration
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