Faraday cage would block this, but any sensory equip would be toasted though. Follow up with HE using GPS.
There was a doomsday device created long ago using the earth:
Tesla Lightning Experiments | eHow.com
"Tesla had some success with his experiments, and they were spectacular. He was able to generate an artificial lightning bolt 135 feet long. The area around the lab glowed when some of the experiments were in session. He lighted vacuum bulbs stuck in the ground at a distance of 25 miles without a wire connection. Some of these experiments took a tremendous amount of power and disabled the generator for all the power to Colorado Springs."