Patent ID: 8581593
Filing Date: 2013-11-12
Classification: G01R,G01V

Abstract:
1. An underground electromagnetic exploration method that uses an induced current generating transmitter that cyclically generates an induced current, the method comprising: repeating magnetic field observation at a plurality of measurement points on the earth's surface, the magnetic field observation including an observation step that observes a magnetic field including a magnetic field signal based on an output from the induced current generating transmitter using a magnetic field sensor device that includes a sensor section and a rod-shaped core section, wherein the sensor section includes a magneto-impedance device having a magnetic amorphous structure, and wherein the rod-shaped core section guides a magnetic field to the magnetic amorphous structure and is disposed in a longitudinal direction with respect to the magnetic amorphous structure, a storage step that stores magnetic field observational data including the magnetic field signal based on the output from the induced current generating transmitter, and a correction step that corrects a reference value of observational data so that the observational data falls within a desired range based on a value obtained by integrating the observational data for a period in which an integral value of the magnetic field signal based on the output from the induced current generating transmitter is zero; and calculating an underground specific resistivity distribution based on the observational data corresponding to each of the plurality of measurement points.