Attenuation of Electric Field Eradiated by Underground Source

摘要

In the paper, the expressions of subaerial electric field (lower frequency) eradiated by a unit electric current source horizontally placed underground is derived for half-space using the method of image charges and numerical calculations are also performed for various epicentral distances (≤ 500Km),several different frequencies (1Hz, 10Hz,100Hz,1KHz) and depths of the source (≤ 30Km). It is found that attenuation of electric field is much smart with depth of electric current source, frequency, and epicentral distance increasing. According to actual threshold for observation of electric field, the condition and possibility for detection of SES is also discussed.