A review of electromagnetic exploration techniques and their applications in East Asia

Electromagnetic (EM) exploration techniques, as powerful and important geophysical tools, have been extensively used in researches ranging from tectonics and resource exploration to environmental and engineering studies. These tools have also proven their applicability to such emerging fields as ocean and airborne surveys. In this article, we quantitatively and qualitatively review advances and applications of EM-exploration studies in East Asia during the past 20 years. During these last two decades, the field of electromagnetic exploration has grown fast, as shown in the increase in the number of related published articles. These studies focus mostly on the development of system platforms (space, aerial, marine) and on data-processing technologies (inversion algorithms, noise reduction). However, most EM applications have been limited to professional geophysics activities. Along with advances in electronics and sensor technologies, EM-exploration instruments are likely to evolve into a modularized open-access system that will become available to more and more scientists at lower and lower costs.