A method for mapping the resistivity distribution of subsurface portions within the earth, comprising the steps of: deploying an electromagnetic source in a borehole; deploying an array of electric field sensors adjacent to the surface of the earth aligned radially to the borehole; transmitting an electromagnetic field from the source at a first depth in the borehole; transmitting an electromagnetic field from the source at a second depth in the borehole; measuring the transmitted electromagnetic fields from the source at the first depth and the second depth with the deployed electromagnetic field sensors; obtaining a ratio of the measured electromagnetic fields from the sensors for source transmissions at the first and second depths; characterized in that the method further comprises: obtaining a measure of radial and tangential components, respectively, of sensed electromagnetic fields at the electric field sensors along a tangential axis, along which a sensed electromagnetic signal is minimum, and along a radial axis at a position orthogonal to the tangential axis; obtaining a measure of the resistivity at the sensors based on the obtained ratio of measured electromagnetic fields from the sensors and the measure of radial and tangential components; and mapping the resistivity distribution of the subsurface from the obtained measures of resistivity at the sensors. deploying an electromagnetic source in a borehole; deploying an array of electric field sensors adjacent to the surface of the earth aligned radially to the borehole; transmitting an electromagnetic field from the source at a first depth in the borehole; transmitting an electromagnetic field from the source at a second depth in the borehole; measuring the transmitted electromagnetic fields from the source at the first depth and the second depth with the deployed electromagnetic field sensors; obtaining a ratio of the measured electromagnetic fields from the sensors for source transmissions at the first and second depths; characterized in that the method further comprises: obtaining a measure of radial and tangential components, respectively, of sensed electromagnetic fields at the electric field sensors along a tangential axis, along which a sensed electromagnetic signal is minimum, and along a radial axis at a position orthogonal to the tangential axis; obtaining a measure of the resistivity at the sensors based on the obtained ratio of measured electromagnetic fields from the sensors and the measure of radial and tangential components; and mapping the resistivity distribution of the subsurface from the obtained measures of resistivity at the sensors. obtaining a measure of radial and tangential components, respectively, of sensed electromagnetic fields at the electric field sensors along a tangential axis, along which a sensed electromagnetic signal is minimum, and along a radial axis at a position orthogonal to the tangential axis; obtaining a measure of the resistivity at the sensors based on the obtained ratio of measured electromagnetic fields from the sensors and the measure of radial and tangential components; and mapping the resistivity distribution of the subsurface from the obtained measures of resistivity at the sensors.