Improving the Quality of Magnetotelluric Data Around Lembang Fault Area Based on Coherence Analysis Muhammad Zulfansyah Saepul Mutaqin (a), Nurhasan (a*), Gusti Muhammad Lucki Junursyah (b), Hidayat (b), Ahmad Setiawan (b), Randi Rusdiana (a), Ihyaudin Hasbillah (a)
a) Earth Physics and Complex System, Bandung Institute of Technology
Jalan Ganesha 10, Bandung 40132, Indonesia
*nurhasan[at]itb.ac.id
b) Center For Geological Survey, Geological Agency, Ministry of Energy and Mineral Resources
Jl. Diponegoro 57, Bandung 40122, Indonesia
Abstract
Magnetotelluric is a passive geophysical method that measures variations in the Earth^s natural electric and magnetic fields to observe subsurface conditions at depths of up to 10 kilometres. The physical parameters produced by this method are the resistivity properties of the subsurface layer. The main problem with the magnetotelluric method is the influence of noise that affects data quality. Noise that is often encountered in the field is AC current generated from household electricity and regional lightning. The quality of data affected by noise needs to be improved to obtain good interpretation results and approach the actual conditions below the surface. This study aims to reduce the influence of coherent noise through data processing based on coherence values. Data obtained at 5 points around the Lembang Fault and close to the population. Increasing the coherence value through several stages of the process, namely using robust, time series, and edit cross power (XPR). The results obtained are proven to increase the coherence value by up to 20 Percent. This study aims to prove that the detected noise can be reduced to improve the quality of MT data to obtain the actual subsurface conditions.
