The Enhancement of Magnetotelluric Surveying via Natural Wave Field Predictions and Artificial Wave Injection Experiments

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Magnetotelluric (MT) techniques, which employ ultra low frequency electromagnetic waves in order to reveal subsurface geological structures are becoming increasingly important tools for geological exploration, particularly under conditions where standard seismic methods are expensive to implement or produce ambiguous results. A major drawback of present MT methods is a reliance on sporadically occurring natural sources of such waves or highly localised controlled sources in the form of a small transmitter towed along by an ocean going survey vessel. Over the past three decades techniques have been developed which allow ultra low frequency electromagnetic waves to be artificially excited in the Earth's upper atmosphere by irradiating it with modulated high power, high frequency radio waves from ground-based transmitters. This programme will explore the use of such experiments, and the forecasting of naturally-occurring waves, in order to improve the efficiency and cost-effectiveness of current MT survey techniques.