Ravat, D., K. Kirkham, and T.G. Hildenbrand, A source-depth separation filter: Using the Euler method on the derivatives of total intensity magnetic anomaly data, The Leading Edge, 21, 360-365, 2002.
Abstract
Derivatives of potential-field anomalies (or the anomaly gradients) enhance the field associated with shallow features and de-emphasize the field from deeper sources. The derivative approach of separating anomalies of shallow, intermediate, and deep sources is, however, qualitative.
Semiautomatic source location methods, such as the Euler method (also variously referred to as Euler's theorem on homogeneous functions, Euler's differential equation, EULDPH, and Euler deconvolution), the analytic signal method, and Werner deconvolution, developed since the 1980s use anomaly gradients to characterize sources of anomalies (i.e., the type of sources and their locations).
In this article, we investigate the benefits of applying the Euler method on derivatives of anomalies to enhance the location of shallow and deep sources. Used appropriately, the method is suitable for characterizing sources from all potential-field data and/or their derivatives, as long as the data can be regarded mathematically as "continuous." We also explain the reasons why the use of the Euler method on derivatives of anomalies is particularly helpful in the analysis and interpretation of shallow features.
Suggested Readings
- "Magnetic terranes in central USA from the interpretation of digital data" by Hildenbrand (in The Utility of Regional Gravity and Magnetic Anomaly Maps, SEG, 1985).
- "Geophysical setting of the Wabash Valley Fault System" by Hildenbrand and Ravat (Seismological Research Letters, 1997).
- "Depth to magnetic source using the generalized analytic signal" by Hsu et al. (GEOPHYSICS, 1998).
- "Imaging magnetic sources using Euler's equation" by Hsu (Geophysical Prospecting, 2002).
- Investigations of a High-Resolution Aeromagnetic Survey over the Southeastern Portion of the Illinois Basin by Kirkham (master's thesis, Southern Illinois University Carbondale, 2001).
- "Analysis of the Euler method and its applicability in environmental magnetic investigations" by Ravat (Journal of Environmental and Engineering Geophysics, 1996).
- Gradients in the interpretation of satellite-altitude magnetic data: An example from Central Africa" by Ravat et al. (Journal of Geodynamics, 2002).
- "Magnetic interpretation in three dimensions using Euler deconvolution" by Reid et al. (GEOPHYSCIS, 1990).
- Paleomagnetic and 40 Ar/39Ar Results from the Grant Intrusive Breccia and Comparison to the Permian Downeys Bluff Sill¾Evidence for Permian Igneous Activity at Hicks Dome, Southern Illinois Basin by Reynolds et al. (USGS Bulltein 2094-G, 1997).