# Potential Fields **URL:** https://simpeg.discourse.group/c/potential-fields/6.md [Latest](https://simpeg.discourse.group/latest.md) · [Categories](https://simpeg.discourse.group/categories.md) --- ## [About the Potential Fields category](https://simpeg.discourse.group/t/about-the-potential-fields-category/14)
**Author:** [@lheagy](https://simpeg.discourse.group/u/lheagy)\ **Replies:** 2\ **Last updated:** [January 3, 2022, 5:30am UTC](https://simpeg.discourse.group/t/about-the-potential-fields-category/14 "2022-01-03T05:30:28Z")
This is a space for talking about simulations and inversions of potential fields data. Ask your questions or post ideas about gravity and magnetics here! --- ## [Posterior uncertainty on a published gravity inversion: the gates, a retraction, and what I got wrong](https://simpeg.discourse.group/t/posterior-uncertainty-on-a-published-gravity-inversion-the-gates-a-retraction-and-what-i-got-wrong/807)
**Author:** [@vaishak-vn](https://simpeg.discourse.group/u/vaishak-vn)\ **Replies:** 0\ **Last updated:** [August 2, 2026, 7:25am UTC](https://simpeg.discourse.group/t/posterior-uncertainty-on-a-published-gravity-inversion-the-gates-a-retraction-and-what-i-got-wrong/807 "2026-08-02T07:25:42Z")
Hi all. I’m Vaishak, coming from software and ML rather than geophysics, so please read this with that in mind. Over the last few months I reproduced a published potential-field inversion and computed the posterior unce… --- ## [Inversion of magnetization amplitude with different direction than external field](https://simpeg.discourse.group/t/inversion-of-magnetization-amplitude-with-different-direction-than-external-field/737)
**Author:** [@clairebouligand](https://simpeg.discourse.group/u/clairebouligand)\ **Replies:** 4\ **Last updated:** [March 26, 2026, 7:06pm UTC](https://simpeg.discourse.group/t/inversion-of-magnetization-amplitude-with-different-direction-than-external-field/737 "2026-03-26T19:06:21Z")
Hi, I would like to know if this is possible to do an inversion of magnetization or pseudo-susceptibility assuming the magnetization direction is different from the external field. I have tested the mvi inversion by imp… --- ## [Relevant contents of seismic refraction forward and inversion](https://simpeg.discourse.group/t/relevant-contents-of-seismic-refraction-forward-and-inversion/367)
**Author:** [@Hui](https://simpeg.discourse.group/u/Hui)\ **Replies:** 8\ **Last updated:** [December 10, 2025, 2:39pm UTC](https://simpeg.discourse.group/t/relevant-contents-of-seismic-refraction-forward-and-inversion/367 "2025-12-10T14:39:42Z")
Hello, I’m a university student majoring in geophysics. I want to ask you a question: Is there any code related to seismic refraction forward and inversion in simpeg? I would be very happy if you could spare me precious … --- ## [Cross-Gradient Joint Inversion](https://simpeg.discourse.group/t/cross-gradient-joint-inversion/723)
**Author:** [@33geo](https://simpeg.discourse.group/u/33geo)\ **Replies:** 0\ **Last updated:** [June 11, 2025, 12:59pm UTC](https://simpeg.discourse.group/t/cross-gradient-joint-inversion/723 "2025-06-11T12:59:01Z")
Dear all, I am currently using the SimPEG library, which I consider to be an exceptionally robust and versatile computational tool. At present, I am performing a joint inversion of gravity and magnetic data using the cr… --- ## [SimPEG v0.23.0 Magnetic Susceptibility Inversion Error - TypeError: Object must be an instance of Data](https://simpeg.discourse.group/t/simpeg-v0-23-0-magnetic-susceptibility-inversion-error-typeerror-object-must-be-an-instance-of-data/706)
**Author:** [@kk333](https://simpeg.discourse.group/u/kk333)\ **Replies:** 0\ **Last updated:** [April 13, 2025, 6:46am UTC](https://simpeg.discourse.group/t/simpeg-v0-23-0-magnetic-susceptibility-inversion-error-typeerror-object-must-be-an-instance-of-data/706 "2025-04-13T06:46:38Z")
Hello SimPEG community, I’m working on a magnetic data processing and susceptibility inversion application. After successfully implementing the data processing part (gridding, RTP, upward continuation), I’m encountering… --- ## [Can I use IRLS (e.g., Lp-norm) regularization on the gravity and magnetic models while still using cross-gradient as a coupling term?](https://simpeg.discourse.group/t/can-i-use-irls-e-g-lp-norm-regularization-on-the-gravity-and-magnetic-models-while-still-using-cross-gradient-as-a-coupling-term/694)
**Author:** [@Mr.Xingfeng](https://simpeg.discourse.group/u/Mr.Xingfeng)\ **Replies:** 0\ **Last updated:** [April 3, 2025, 1:31pm UTC](https://simpeg.discourse.group/t/can-i-use-irls-e-g-lp-norm-regularization-on-the-gravity-and-magnetic-models-while-still-using-cross-gradient-as-a-coupling-term/694 "2025-04-03T13:31:59Z")
I’m working on a joint inversion of gravity and magnetic data in SimPEG, and I want to incorporate cross-gradient coupling between the two models. I know that SimPEG supports IRLS for sparsity-promoting regularization … --- ## [Understanding of the mathematical framework](https://simpeg.discourse.group/t/understanding-of-the-mathematical-framework/639)
**Author:** [@33geo](https://simpeg.discourse.group/u/33geo)\ **Replies:** 1\ **Last updated:** [March 26, 2025, 2:40am UTC](https://simpeg.discourse.group/t/understanding-of-the-mathematical-framework/639 "2025-03-26T02:40:18Z")
Congratulations! SimPEG is truly an incredible tool! I recently started using it and would like to deepen my understanding of the mathematical framework underlying the forward modeling and inverse problem. Could you kind… --- ## [Gravity inversion for four bodies](https://simpeg.discourse.group/t/gravity-inversion-for-four-bodies/682)
**Author:** [@Anish](https://simpeg.discourse.group/u/Anish)\ **Replies:** 0\ **Last updated:** [March 25, 2025, 8:01am UTC](https://simpeg.discourse.group/t/gravity-inversion-for-four-bodies/682 "2025-03-25T08:01:49Z")
Hi everyone, I have a question regarding the gravity inversion, as in the tutorial it is used with two bodies, one block, and one sphere, but I am using the four bodies with two spheres and two blocks. I performed the f… --- ## [Joint inversion for grav and mag](https://simpeg.discourse.group/t/joint-inversion-for-grav-and-mag/645)
**Author:** [@GoatSuey](https://simpeg.discourse.group/u/GoatSuey)\ **Replies:** 0\ **Last updated:** [December 19, 2024, 3:53pm UTC](https://simpeg.discourse.group/t/joint-inversion-for-grav-and-mag/645 "2024-12-19T15:53:59Z")
Hi all, I have been using SimPEG cross gradient inversion code for gravity and magnetics for a while and although it works fine I want to ask: Is it possible to add borehole data and e.g. a density model as prior infor… --- ## [2D density model for salt domes](https://simpeg.discourse.group/t/2d-density-model-for-salt-domes/609)
**Author:** [@Aseem](https://simpeg.discourse.group/u/Aseem)\ **Replies:** 0\ **Last updated:** [September 26, 2024, 2:09am UTC](https://simpeg.discourse.group/t/2d-density-model-for-salt-domes/609 "2024-09-26T02:09:17Z")
Hi everyone, I am looking to generate 2D density models of salt domes in various shapes. Could you provide suggestions or recommendations on how to build random models representing salt bodies? Thanks --- ## [Error in inversion algorithm for PGI inversion when setting GMM update = True](https://simpeg.discourse.group/t/error-in-inversion-algorithm-for-pgi-inversion-when-setting-gmm-update-true/603)
**Author:** [@Mridul](https://simpeg.discourse.group/u/Mridul)\ **Replies:** 1\ **Last updated:** [August 28, 2024, 5:10pm UTC](https://simpeg.discourse.group/t/error-in-inversion-algorithm-for-pgi-inversion-when-setting-gmm-update-true/603 "2024-08-28T17:10:04Z")
Greetings, As a young researcher being in initial days of work, I was working on exploring the PGI inversion of Gravity data. I have been stuck to a point where the inversion code interrupts saying: ValueError … --- ## [Performance scaling for potential field problems](https://simpeg.discourse.group/t/performance-scaling-for-potential-field-problems/594)
**Author:** [@williamdavisterraai](https://simpeg.discourse.group/u/williamdavisterraai)\ **Replies:** 1\ **Last updated:** [August 20, 2024, 9:41pm UTC](https://simpeg.discourse.group/t/performance-scaling-for-potential-field-problems/594 "2024-08-20T21:41:17Z")
Does anyone know if there are any performance benchmarks or scaling analysis results for SimPEGs forward modeling methods? I’ve looked around, and I can only find information on the inverse step. --- ## [Help with 3D gravity forward modelling](https://simpeg.discourse.group/t/help-with-3d-gravity-forward-modelling/592)
**Author:** [@Lorenzo](https://simpeg.discourse.group/u/Lorenzo)\ **Replies:** 0\ **Last updated:** [August 1, 2024, 12:34pm UTC](https://simpeg.discourse.group/t/help-with-3d-gravity-forward-modelling/592 "2024-08-01T12:34:25Z")
Hi there. I’m trying to do gravity forward modelling on a large model of about 2020 40 km, characterised by 2 density layers (a mantle with a crustal root and a crust), 2 sphere sources in the crust and a very simple top… --- ## [Guidance for gravity and magnetic data inversion](https://simpeg.discourse.group/t/guidance-for-gravity-and-magnetic-data-inversion/552)
**Author:** [@saifkhan](https://simpeg.discourse.group/u/saifkhan)\ **Replies:** 0\ **Last updated:** [March 7, 2024, 10:11am UTC](https://simpeg.discourse.group/t/guidance-for-gravity-and-magnetic-data-inversion/552 "2024-03-07T10:11:43Z")
I need to invert the gravity and magnetic data to get the subsurface density variation ,along with the Moho depth and curie. Can anyone help me which tutorial to follow and what will be the input data for the same. --- ## [" 'irls\_threshold' must be a value in the range (0.0, inf\]"](https://simpeg.discourse.group/t/irls-threshold-must-be-a-value-in-the-range-0-0-inf/544)
**Author:** [@zhongmin\_zhu](https://simpeg.discourse.group/u/zhongmin_zhu)\ **Replies:** 0\ **Last updated:** [January 31, 2024, 2:17pm UTC](https://simpeg.discourse.group/t/irls-threshold-must-be-a-value-in-the-range-0-0-inf/544 "2024-01-31T14:17:47Z")
Dear all: I am doing some inversion test using spontaneous\_potential moudel within simpeg. When I use the sparse regularization class to constrain the inversion result using an IRLS approach, I got a mistake " ‘irls\_t… --- ## [How is remanent magnetization/remanence handled in forward modelling?](https://simpeg.discourse.group/t/how-is-remanent-magnetization-remanence-handled-in-forward-modelling/540)
**Author:** [@jariswanson](https://simpeg.discourse.group/u/jariswanson)\ **Replies:** 0\ **Last updated:** [January 17, 2024, 7:01am UTC](https://simpeg.discourse.group/t/how-is-remanent-magnetization-remanence-handled-in-forward-modelling/540 "2024-01-17T07:01:17Z")
I am looking to perform magnetic forward modelling considering both remanence and susceptibility, and I do not understand how the remanent component is specified in models. Specifically in the following example, what ex… --- ## [How to improve the skin effect in the inversion process?](https://simpeg.discourse.group/t/how-to-improve-the-skin-effect-in-the-inversion-process/461)
**Author:** [@YULJ](https://simpeg.discourse.group/u/YULJ)\ **Replies:** 1\ **Last updated:** [November 14, 2023, 7:51am UTC](https://simpeg.discourse.group/t/how-to-improve-the-skin-effect-in-the-inversion-process/461 "2023-11-14T07:51:48Z")
Hello everyone, I have few doubts that need to be addressed in my gravity inversion work. The questions are as follows: How to use depth\_weighting in my inversion work? (Maby i could use reg.set\_weights?) When th… --- ## [Joint inversion of potential filed data using cross-gradient constraint](https://simpeg.discourse.group/t/joint-inversion-of-potential-filed-data-using-cross-gradient-constraint/519)
**Author:** [@Bard](https://simpeg.discourse.group/u/Bard)\ **Replies:** 0\ **Last updated:** [November 2, 2023, 9:53am UTC](https://simpeg.discourse.group/t/joint-inversion-of-potential-filed-data-using-cross-gradient-constraint/519 "2023-11-02T09:53:32Z")
Hello, I am currently working on the cross-gradient joint inversion method for gravity and magnetic data in the context of iron deposits. My question is about the joint inversion Jupyter notebook in the SimPEG documentat… --- ## [Insert a void space in gravity forward model](https://simpeg.discourse.group/t/insert-a-void-space-in-gravity-forward-model/487)
**Author:** [@rana](https://simpeg.discourse.group/u/rana)\ **Replies:** 0\ **Last updated:** [August 2, 2023, 4:15am UTC](https://simpeg.discourse.group/t/insert-a-void-space-in-gravity-forward-model/487 "2023-08-02T04:15:43Z")
I want to insert a void space ~300 m below the topography surface. The xyz of coordinates of the void space is given in a text file and it is in much smaller discretization than the mesh. I was wondering would there be a… --- ## [The shape of the model in PGI joint inversion is not matched](https://simpeg.discourse.group/t/the-shape-of-the-model-in-pgi-joint-inversion-is-not-matched/456)
**Author:** [@Hui](https://simpeg.discourse.group/u/Hui)\ **Replies:** 1\ **Last updated:** [June 5, 2023, 3:02pm UTC](https://simpeg.discourse.group/t/the-shape-of-the-model-in-pgi-joint-inversion-is-not-matched/456 "2023-06-05T15:02:14Z")
Hello, I am trying to perform a two-dimensional joint inversion of resistivity method and seismic straight-ray tomography imaging using the PGI framework. I used the existing examples in simpeg for their forward simulati… --- ## [Sign Convention for gravity anomalies while inverting actual datasets](https://simpeg.discourse.group/t/sign-convention-for-gravity-anomalies-while-inverting-actual-datasets/433)
**Author:** [@akamath](https://simpeg.discourse.group/u/akamath)\ **Replies:** 2\ **Last updated:** [April 16, 2023, 3:16pm UTC](https://simpeg.discourse.group/t/sign-convention-for-gravity-anomalies-while-inverting-actual-datasets/433 "2023-04-16T15:16:04Z")
Hello again, I have reviewed the sign convention information for the forward gravity operator in SimPEG. I have a few doubts I was hoping someone could solve. If the sign convention for the forward operator differs, … --- ## [Running the PGI Joint Inversion Code for simulated data](https://simpeg.discourse.group/t/running-the-pgi-joint-inversion-code-for-simulated-data/416)
**Author:** [@akamath](https://simpeg.discourse.group/u/akamath)\ **Replies:** 6\ **Last updated:** [April 3, 2023, 4:36am UTC](https://simpeg.discourse.group/t/running-the-pgi-joint-inversion-code-for-simulated-data/416 "2023-04-03T04:36:15Z")
Greetings! I have been testing and using the PGI formulation in SimPEG as the basis for my master’s thesis and I have some questions I was hoping to get answers to. The Solver problem: I was using an earlier version o… --- ## [Gridding Geophysical Aeromagnetic Data from XYZ data in order to obtain a Grid with Magnetic Field, Elevation and other columns using Python or Simpeg](https://simpeg.discourse.group/t/gridding-geophysical-aeromagnetic-data-from-xyz-data-in-order-to-obtain-a-grid-with-magnetic-field-elevation-and-other-columns-using-python-or-simpeg/411)
**Author:** [@mandalfred](https://simpeg.discourse.group/u/mandalfred)\ **Replies:** 1\ **Last updated:** [April 2, 2023, 2:10pm UTC](https://simpeg.discourse.group/t/gridding-geophysical-aeromagnetic-data-from-xyz-data-in-order-to-obtain-a-grid-with-magnetic-field-elevation-and-other-columns-using-python-or-simpeg/411 "2023-04-02T14:10:27Z")
Hello I have Geophysical aeromagnetic data that was collected in 2014 via the Helicopter. The raw data consist of XYZ whereby the X and Y is the location and the Z is the depth. I use Ubuntu Linux and I wanted to use th… --- ## [Analysis step error, reordering problem](https://simpeg.discourse.group/t/analysis-step-error-reordering-problem/398)
**Author:** [@shreya](https://simpeg.discourse.group/u/shreya)\ **Replies:** 1\ **Last updated:** [December 15, 2022, 6:55pm UTC](https://simpeg.discourse.group/t/analysis-step-error-reordering-problem/398 "2022-12-15T18:55:36Z")
Hello, I get the error “PardisoError: Analysis step error, reordering problem ” during inversion. pgi\_model = inv.run(m0) I use SimPEG v0.17.0. Here the traceback: PardisoError Tracebac… --- ## [An error on regional gravity inversion](https://simpeg.discourse.group/t/an-error-on-regional-gravity-inversion/390)
**Author:** [@VTeknik](https://simpeg.discourse.group/u/VTeknik)\ **Replies:** 1\ **Last updated:** [December 8, 2022, 4:38pm UTC](https://simpeg.discourse.group/t/an-error-on-regional-gravity-inversion/390 "2022-12-08T16:38:05Z")
Hi everyone, For the following codes, I have an error. Do you have any idea: Compute the source field receiver\_list = gravity.receivers.Point(receiver\_locations, components=\[“gz”\]) receiver\_list = \[receiver\_list\] src… --- ## [Attribute error in gravity inversion](https://simpeg.discourse.group/t/attribute-error-in-gravity-inversion/353)
**Author:** [@Jenny](https://simpeg.discourse.group/u/Jenny)\ **Replies:** 2\ **Last updated:** [September 2, 2022, 12:18am UTC](https://simpeg.discourse.group/t/attribute-error-in-gravity-inversion/353 "2022-09-02T00:18:57Z")
Hi, I recently updated my geoapps. When I tried to run a gravity inversion, I got the following error and I don’t know what to do. Help please. Thanks. AttributeError Traceback (most recent c… --- ## [Integral VS Differential Formulation](https://simpeg.discourse.group/t/integral-vs-differential-formulation/351)
**Author:** [@1apsus](https://simpeg.discourse.group/u/1apsus)\ **Replies:** 3\ **Last updated:** [August 22, 2022, 3:50pm UTC](https://simpeg.discourse.group/t/integral-vs-differential-formulation/351 "2022-08-22T15:50:06Z")
Hello everyone, I’ve noticed that in PF mag/gravity, SimPEG is using the integral formulation instead of the differential formulation used for almost all the other types of the SimPEGs problems. My questions are: Why… --- ## [Calculating Gz from Gzz](https://simpeg.discourse.group/t/calculating-gz-from-gzz/345)
**Author:** [@Jenny](https://simpeg.discourse.group/u/Jenny)\ **Replies:** 2\ **Last updated:** [August 21, 2022, 10:01pm UTC](https://simpeg.discourse.group/t/calculating-gz-from-gzz/345 "2022-08-21T22:01:55Z")
Hi, I have recently learned how to use Gravity and Magnetic 3D Inversion in geoapps. Since SimPEG uses an integral equation approach, does this mean I can produce Gz when I perform inversion on Gzz data? If so, at whic… --- ## [Is it possible to get the maximum and minimum values of Normalized Misfit are larger than the Observed or Predicted Gravity anomaly values?](https://simpeg.discourse.group/t/is-it-possible-to-get-the-maximum-and-minimum-values-of-normalized-misfit-are-larger-than-the-observed-or-predicted-gravity-anomaly-values/285)
**Author:** [@sant\_63](https://simpeg.discourse.group/u/sant_63)\ **Replies:** 1\ **Last updated:** [June 6, 2022, 7:12pm UTC](https://simpeg.discourse.group/t/is-it-possible-to-get-the-maximum-and-minimum-values-of-normalized-misfit-are-larger-than-the-observed-or-predicted-gravity-anomaly-values/285 "2022-06-06T19:12:43Z")
Hello, everyone Myself Santosh Kumar, PhD Student at Department of Applied Geophysics, IIT(ISM), Dhanbad, India. I congratulate to all SimPEG Contributors. SimPEG is amazing !! I am using SimPEG since few months … [Next page](https://simpeg.discourse.group/c/potential-fields/6.md?page=1)