NEW ELECTRICAL IMAGING SYSTEM IN ALTERNATE CURRENT MOD. POLARES - P.A.S.I. - #1

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NEW ELECTRICAL IMAGING SYSTEM IN ALTERNATE CURRENT MOD. POLARES www.pasisrl.it PRELIMINARY Applications • Shallow detailed investigations of pollutant plums in the ground • Archeological surveys • Waste site doposit monitoring • Mapping and monitoring of salty water conta mination of groundwater reservoirs along coastal areas POLARES P.A.S.I. S.R.L. — Via Galliari 5/E — 10125 Torino tel. 011 6507033 — fax 011 658646 oppure 6692166 e-mail: info@pasisrl.it www.pasisrl.it Until now electrical imaging applied to geophysical exploration have been using the same traditional method for acquiring data: an electric current was applied between two electrodes and the correspondent voltage was measured between other two electrodes inserted in the ground. Applied current and the related voltage were always continuous, with an inversion of polarity for each measurement. The new POLARES now uses a sinusoidal alternate current of variable frequency. Even if the instrument designing could be more complicated, the use of alternate current had showned great advantages, in particular considering the absolutely greater velocity of acquisitions, that may increase of at least 10 times in respect of standard DC measuring time. Moreover, the measurement of the ratio between Voltage and Current can be done in a sinusoidal condition for both module and phase (delay of a signal in respect of the other); these two informations, obtaineble with a single measurement, allow the system to acquire both resistivity and IP data.