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Estimation of Depth to Bottom of Magnetic Sources Using Spectral Methods: Application on Iran's Aeromagnetic Data
Author(s) -
Kumar Raj,
Bansal A. R.,
Ghods Abdolreza
Publication year - 2020
Publication title -
journal of geophysical research: solid earth
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.983
H-Index - 232
eISSN - 2169-9356
pISSN - 2169-9313
DOI - 10.1029/2019jb018119
Subject(s) - geology , centroid , fractal , block (permutation group theory) , plateau (mathematics) , geodesy , seismology , geometry , mathematics , mathematical analysis
The effect of window size while estimating the depth to bottom of magnetic sources (DBMS) is examined on the synthetic 2‐D magnetic field data. The data are generated for 3‐D fractal magnetization models assuming different combinations of depth to the top and bottom of magnetic sources. The depths are estimated assuming an uncorrelated and correlated random distribution of sources. The depths to the top estimated for fractal distribution of sources are found within 70% of the true values for all window sizes, whereas the values for the uncorrelated random distributions are far from the real depths. The DBMS for the correlated random distribution of sources are estimated within 70–80% of the true values for the window sizes of 5 times or more of the targeted depths. The modified centroid method is found to provide better estimations as compared to scaling‐spectral peak modeling. The modified centroid method is applied to the aeromagnetic data of Iran to estimate the DBMS using a window size of 200 × 200 km 2 . The shallow DBMS between 12 and 20 km are obtained for the Quaternary Sabalan and Sahand volcanoes to the NW of Iran, the central and NE of central Iran, the central Zagros, NW of Tabas block, and the south of the Lut Block. The deepest DBMS of the order of 40 km is found in the Makran. The rest of Iranian Plateau is characterized by DBMS of 20 to 30 km. The shallow DBMS are found in correlation with the depth of the Ophiolites.