Developing a synchronized multichannel magnetotelluric system for imaging the subsurface structures in Taichung Da-Keng area

• Main Authors: Huei-Guo Jhou, 周暉國
• Other Authors: Ping-Yu Chang
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/5mdg95

碩士 === 國立中央大學 === 地球科學學系 === 105 === Magnetotelluric method is a non-destructive geophysical prospecting method of passive source. The station will record the changes of natural electric and magnetic fields to calculate the impedance tensors and apparent resistivity curves for understanding the local underground electrical structure. The market of commercial magnetotelluric instruments are with various kinds, but because the mode of standardization, and Price expensive. So in the case of limited resources, often limit the flexibility and efficiency of the construction survey. The present study was used development the synchronized multichannel magnetotelluric system. The self-developed instrument is the multi-channel system combined with satellite synchronized, high sampling rate record, one three-axis fluxgate magnetometer and the non-polarized electrodes. In the Taichung and Ilan area, we used commercial magnetotelluric measuring instruments and self-developed systems jointly determining the consistency and correctness. We set up several simultaneous sequence magnetotelluric station in Taichung Da-Keng region with self-developed magnetotelluric instrument at the same time for testing the equipment and signal collection, and the self-developed calculation program was applied to process the collected data. In our data processing, we use a notch filter to filter out the power line interference, and employ the cross power spectrum operation, to improve the correlation between signals, and the parzen window computing the specific frequency spectrum, and then calculate the apparent resistivity values with robust fit. We verified the processing program effectiveness and accuracy in magnetotelluric measuring system. We will use this magnetotelluric system in future to investigate the of Taiwan's Geoelectrical section.