2009 Geoscience BC Scholarship Recipients

Dikun Yang, PhD student, University of British Columbia

PhD Thesis - Dikun Yang
Geophysical survey decomposition and efficient 3D inversion of time-domain electromagnetic data - University of British Columbia, 2014 - Available digitally through University of British Columbia (pdf, 23.09MB)

Biography: Dikun Yang, an international student from China, started his post-secondary education in the Department of Geophysics, China University of Geosciences Wuhan in 2001. He received his B.S. with major of geophysics in 2005. He then was admitted to the graduate program in China University of Geosciences. From 2005 to 2008, Dikun specialized in electromagnetic methods of applied geophysics, including both theoretical aspects and applications of magnetotelluric, controlsource frequency domain EM, time domain EM, etc. Most of his researches during that period were aiming at solving practical problems arising from industry by geophysical tools, like detection of groundwater, exploration of metallic and coal deposits and evaluation of geohazard. In 2008, Dikun obtained his Master's degree with his thesis study on three-dimensional magnetotelluric inversion of field data. Now Dikun is a PhD student in Geophysical Inversion Facility, Department of Earth and Ocean Sciences, UBC, where he has been researching electromagnetic methods and their applications in mineral exploration under the supervision of Prof. Oldenburg. Currently, his is studying time domain methods using active loop sources with emphases on survey design, data processing and inversion.

Project: Commonly-used time domain electromagnetic method for exploration employ coil or loop as receiver measuring magnetic field related B-field or dB/dt. Since the electric (E-) and magnetic (H-) fields are physically symmetric in Maxwell's Equations and thus must be equally informative, we are trying to develop a new exploration technique called "E-field Time Domain Electromagnetic Method". This method will work in time domain with transient waveform in inductive transmitter loop and measure the electric field by grounded electrodes. Some preliminary studies have shown that E-field measurements are sensitive to alteration and have large penetration into the earth so that more information can be supplied to geologists for interpretation and decision making. The key aspects of my thesis research will include:
  1. forward modeling of E-field source and measurement in time domain with some typical deposit models; analysis of E-field sensitivity; summary of pros and cons of E-field;
  2. quantitative interpretation of E-field data using advanced 3D TEM inversion techniques; producing code and utility to obtain 3D structure of conductivity;
  3. survey design for an E-field TEM survey;
  4. optimization of workflow for practical inversion of E-field TEM;
  5. comparison between E-field TEM and H-field TEM in all technical aspects; conclusion of Efield and H-field behavior in time domain for the purpose of exploration;
  6. field data application.

Roundup 2010 Poster: Inversion of E-Field Time Domain EM Data

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