None of which has anything to do with what happens to a stick of metal held in a sweaty, meaty palm of an animal. Muscle spasms and shifting weight make metal sticks move, not 'electrical fields'.So these seams (maybe a 3 foot wide crack in the limestone) probably extend about 100 feet deep (typical depth of limestone here). Limestone has a dielectric constant of 7 (4-8 if saturated). The clayey soil filling the cracks is likely somewhat saturated and would have a dielectric constant of ~15. Air (cave) has a dielectric constant of 1 and water 78.