A magnetometer notes anomalies in the Earth's magnetic field caused by underground minerals that have or do not have magnetic properties. Any interruption in the profile of those minerals indicates the presence of something significant, such as a huge buried stone.
This story contains 101 words.
Stories older than 90 days are available only to subscribing members. Please help sustain quality local journalism by becoming a subscribing member today.
If you are already a subscriber, please log in so you can continue to enjoy unlimited access to stories and archives. Subscriptions start at $5 per month and may be cancelled at any time.