Exploration Geophysics Exploration Geophysics Society
Journal of the Australian Society of Exploration Geophysicists
RESEARCH ARTICLE

The use of curvature in potential-field interpretation*

Jeffrey D. Phillips 1 4 R. O. Hansen 2 Richard J. Blakely 3
+ Author Affiliations
- Author Affiliations

1 US Geological Survey, Denver Federal Center, Box 25046, MS 964, Denver, CO 80225, USA.

2 EDCON-PRJ, Inc., 171 South Van Gordon Street, Suite E, Lakewood, CO 80228, USA.

3 US Geological Survey, 345 Middlefield Road, MS 989, Menlo Park, CA 94025, USA.

4 Corresponding author. Email: jeff@usgs.gov

Exploration Geophysics 38(2) 111-119 https://doi.org/10.1071/EG07014
Submitted: 28 June 2006  Accepted: 27 April 2007   Published: 15 June 2007

Abstract

Potential-field anomalies can be transformed into special functions that form peaks and ridges over isolated sources. All special functions have a common mathematical form over an isolated source, which leads to a common equation for estimating the source depth from the peak value and the curvature at the peak. Model-specific special functions, usually calculated from a transformed version of a potential field, are used to estimate the locations of very specific source types. Model-independent special functions calculated from an observed or transformed potential field can be used to estimate the locations of a variety of source types. Vertical integration is a particularly useful transformation for reducing the effects of noise and increasing the coherency of solutions from model-independent special functions. For gridded data, the eigenvalues and eigenvectors of the curvature matrix associated with a quadratic surface that is fitted to a special function within 3 × 3 windows can be used to locate the sources and estimate their depths and strikes. Discrete source locations estimated in this manner can be connected into lines that follow contacts, faults, and other mappable features based on distance and azimuth criteria. These concepts are demonstrated on aeromagnetic data from the Albuquerque basin of New Mexico, USA.

Key words: potential-field, interpretation, curvature, source-location, strike.


Acknowledgements

We thank Mike Webring, Tien Grauch, and two anonymous reviewers for helpful comments on the manuscript.


References

Blakely, R. J., and Simpson, R. W., 1986, Approximating edges of source bodies from magnetic or gravity anomalies Geophysics 51, 1494–1498.
CrossRef |

Cordell L. , and Grauch V. J. S. , 1985, Mapping basement magnetization zones from aeromagnetic data in the San Juan basin, New Mexico, in W. J. Hinze, ed., The Utility of Regional Gravity and Magnetic Anomaly Maps: Society of Exploration Geophysicists, 181–197.

Cordell, L., and McCafferty, A. E., 1989, A terracing operator for physical property mapping with potential field data Geophysics 54, 621–634.
CrossRef |

Grauch, V. J. S., 2001, Using high-resolution aeromagnetic surveys to map subsurface hydrogeology in sediment-filled rift basins: a case study over the Rio Grande rift, central New Mexico, USA Exploration Geophysics 32, 209–213.


Hansen, R. O., and deRidder, E., 2006, Linear feature analysis for aeromagnetic data Geophysics 71, L61–L67.
CrossRef |

Li, X., 2006, Understanding the 3D analytic signal Geophysics 71, L13–L16.
CrossRef |

MacLeod, I. N., Jones, K., and Dai, T. F., 1993, 3-D analytic signal in the interpretation of total magnetic field data at low magnetic latitudes Exploration Geophysics 24, 679–688.


Nabighian, M. N., 1972, The analytic signal of two-dimensional magnetic bodies with polygonal cross-section: its properties and use for automated anomaly interpretation Geophysics 37, 507–517.
CrossRef |

Phillips J. D. , 2000, Locating magnetic contacts: a comparison of the horizontal gradient, analytic signal, and local wavenumber methods: Society of Exploration Geophysicists, Expanded Abstracts, 2000 Technical Program, 1, 402–405.

Pilkington, M., and Keating, P., 2004, Contact mapping from gridded magnetic data—a comparison of techniques Exploration Geophysics 35, 306–311.


Pilkington, M., and Keating, P., 2006, The relationship between local wavenumber and analytic signal in magnetic interpretation Geophysics 71, L1–L3.
CrossRef |

Reid, A. B., Allsop, J. M., Granser, H., Millett, A. J., and Somerton, I. W., 1990, Magnetic interpretation in three dimensions using Euler deconvolution Geophysics 55, 80–91.
CrossRef |

Roberts, A., 2001, Curvature attributes and their application to 3D interpreted horizons First Break 19, 85–100.
CrossRef |

Roest, W. R., and Pilkington, M., 1993, Identifying remanent magnetization effects in magnetic data Geophysics 58, 653–659.
CrossRef |

Roest, W. R., Verhoef, J., and Pilkington, M., 1992, Magnetic interpretation using the 3-D analytic signal Geophysics 57, 116–125.
CrossRef |

Smith, R. S., Thurston, J. B., Dai, T.-F., and MacLeod, I. N., 1998, iSPI—the improved source parameter imaging method Geophys. Prosp. 46, 141–151.


Smith, R. S., Salem, A., and Lemieus, J., 2005, An enhanced method for source parameter imaging of magnetic data collected for mineral exploration Geophys. Prosp. 53, 655–665.
CrossRef |

Sweeney R. E. , Grauch V. J. S. , and Phillips J. D. 2002, Merged digital aeromagnetic data for the Albuquerque and southern Espanola Basins, New Mexico: US Geological Survey Open-File Report 02-205. http://pubs.usgs.gov/of/2002/ofr-02-0205/

Thurston, J. B., and Smith, R. S., 1997, Automatic conversion of magnetic data to depth, dip, and susceptibility contrast using the SPI method Geophysics 62, 807–813.
CrossRef |




1 *Presented at the Australian Earth Sciences Convention, June 2006, Melbourne.


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