A comparison of magnetotelluric impedance estimation effects with cascade and sub-band frequency spectrum calculation methods
Gang ZHANG1(), Xian-Guo TUO2, Xu-Ben WANG3, Huai-Liang LI1
1. School of Environment and Resource, Southwest University of Science and Technology, Mianyang 621010, China 2. Sichuan University of Science & Engineering, Zigong 643000, China 3. Institute of Geophysics, Chengdu University of Technology, Chengdu 610059, China
Cascade and sub-band frequency spectrum calculation are two power spectrum calculation methods in magnetotelluric data processing. This paper is based on Welch power spectrum calculation method, and sets the processing parameters under the same conditions, so as to use two spectrum calculation methods to estimate magnetotelluric impedance with simulated data and field data respectively. The results show that, for both the apparent resistivity and the impedance phase, the two power spectrum calculation methods obtain nearly the same results for the simulated data and the field data; nevertheless, the sounding curve with sub-band frequency spectrum calculation method is more continuous and more reasonable than that with cascade method at lower frequency, while at high frequency, the cascade method can get slightly better curves than sub-band frequency spectrum calculation.
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Gang ZHANG, Xian-Guo TUO, Xu-Ben WANG, Huai-Liang LI. A comparison of magnetotelluric impedance estimation effects with cascade and sub-band frequency spectrum calculation methods. Geophysical and Geochemical Exploration, 2018, 42(1): 185-191.
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