Determining the best 2D model based on tensor impedance rotation on magnetotelluric data

Padjadjaran Earth Dialogues, International Symposium on Geophysical Issues

Maulana, Dimas B.^1 ; Lucki Junursyah, G.M.^2 ; Agustine, Eleonora^1 ; Harja, Asep^1

Geophysics Departement, Padjadjaran University, Jl. Raya Bandung-Sumedang Km 21, Jatinangor, Sumedang

45363, Indonesia^1

Pusat Survei Geologi (PSG), Ministry of Energy and Mineral Resources, Jl. Diponegoro No.57, Jawa Barat, Bandung

40115, Indonesia^2

关键词: Angle rotations;    Data coherence;    Earth's surface;    Lighting activities;    Magnetotelluric data;    Noise reduction methods;    Overlay model;    Subsurface structures;   

Others  :  https://iopscience.iop.org/article/10.1088/1755-1315/311/1/012070/pdf
DOI  :  10.1088/1755-1315/311/1/012070

来源: IOP

【 摘 要 】

Magnetoteluric data can be formed in 2D model, however the data that was used to produce the best 2D model should contain less noise. Field data contains a lot of noise due to the source is derived from the natural activities, like solar wind and lighting activity. One of the noise reduction methods used is time series analysis. The reduction can increase data coherence attain 94.36% from the lowest field data before it is reduced, 40.15%. Time series analysis data was used to describe 2D direction model of the subsurface structure appropriately. However, in the measurements between the magnetic field and the electric field in a perpendicular field are not necessarily had the same direction as the structure beneath the earth's surface, so rotation was needed in order to equate both. There are two types of rotation, strike angle rotation and fix angle rotation. Structural direction in 2D MT modelling can be predicted using invariant impedance by comparing data after strike angle rotation, fix angle rotation and before rotation over overlay model. The strike angle rotation model is the best of the three comparative results by showing the distribution of 67.31% resistivity in the range 1 Ωm - 364 Ωm.