RADIO MAGNETO-TELLURICS - A NEW METHOD IN APPLIED GEOPHYSICS

The principles of the magneto-telluric (M-T) method are recalled and t he three versions are presented: Radio, Audio and Hello M-T. Radio M-T is then discussed with more details with its own sources, its magneti c and telluric sensors, its data acquisition and processing system. Th en the method is analysed through concrete field experiments in variou s situations of civil engineering, hydrogeology, archaeology and pedol ogy. Thus, the main characteristics and advantages of the method are s hown: phenomena are not created by the users, the capacitive telluric sensors are dragged on the ground (electrostatic carpet). The investig ation depth varies with the frequency and concerns typically three lev els in the ground; a few metres and about ten or twenty metres (what i s not to be compared with electrical soundings), interpretation may be qualitative by a direct reading of resistivity profiles or maps in is ovalues or in ranges of grey or colours, or quantitative by elaboratin g models for one, two or three dimensions.