Magnetic Anomaly Map (IMAGE) Naval Research Laboratory Caption The magnetic data are useful for calculating bulk estimates of the magnetic properties of the local rocks and the depth to the magnetic source material, both useful in oil, gas, and mineral exploration. Credit US Geological Survey Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.