The natural-source data-acquisition system typically measures four components: E<sub>x</sub>, E<sub>y</sub>, H<sub>x</sub>, and H<sub>y</sub>. The E<sub>x</sub> component is oriented perpendicular to the E<sub>y</sub> component. This is also true for the H-field components. | The natural-source data-acquisition system typically measures four components: E<sub>x</sub>, E<sub>y</sub>, H<sub>x</sub>, and H<sub>y</sub>. The E<sub>x</sub> component is oriented perpendicular to the E<sub>y</sub> component. This is also true for the H-field components. |