Melo, F. F. and V. C. F. Barbosa (2020) Reliable Euler deconvolution estimates throughout the vertical derivatives of the total-field anomaly, Computers & Geosciences, 138, 104436, doi:10.1016/j.cageo.2020.104436.
We propose a novel methodology to select reliable Euler deconvolution estimates throughout the vertical derivatives of the total-field anomaly, grounded on the capability of this quantity to locate anomalies due to its higher signal decay with distance. In applying Euler deconvolution to a small moving-data window, we compute the standard deviation of the vertical derivatives of the total-field anomaly for each data window. Then, we define the reliable source-location estimates as those estimates that are obtained by using the data windows with the largest standard deviations of the vertical derivatives of the total-field anomaly. For all tentative values of the structural index (SI), the reliable estimates with tight clustering define the correct SI and the mean of these estimates define the source position. We compared our methodology to select reliable Euler source-position estimates with two available methodologies in the literature based on the rejection criteria of data amplitude and of depth uncertainty. We conducted tests on synthetic noise-corrupted data to investigate the sensitivity of our method to deal with the presence of: i) an additive nonlinear background that simulates a regional field; ii) interfering anomalies with distinct amplitudes; iii) weak-, mid-, and strong-interfering anomalies; and iv) distinct noise levels. Most of tests in the sensitivity analysis shows that our methodology to select reliable Euler source-position estimates yielded better interpretation of the simulated magnetic sources than the methodology based on the rejection criteria of data amplitude and of depth uncertainty. The only exception was the tests with high noise levels in which the reliable Euler estimates selected either by our method or by the rejection criteria yielded poor interpretations. Applications to a real aeromagnetic survey from southern Brazil interpreted an isolated plug intrusion over the Anitápolis anomaly and a swarm of shallow-seated dikes with northwest-southeast trend over the Paranaguá Terrane.
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