Explanation of the Earth's gravitational field, emphasizing how USGS scientists measure gravity and portray these measurements on maps. Explains terminology of gravity anomaly maps and their relationship to the rock types and other geologic features.
Links to products of magnetic, gravity, magnetotelluric, and multi-discipline reports and surveys of regions in the U.S. and Antarctica plus geophysical software tools. Some products are in PDF format.
Airborne electromagnetic surveying is used to estimate the character of the permafrost by measuring and monitoring the electrical resistivity, which is affected by lithology, temperature, water, and ice.
Project summary, photos of logging truck, and bibliographies on log interpretation techniques and instrumentation to record geophysical data in wells and test holes for studying ground water hydraulics and evaluate waste disposal sites.
Coordinated studies of the effect of historical mining for mercury, origin and composition of metals in groundwaters and surface waters, history of volcanic and intrusive activity, and the complex geological history of this area.
This publication (Open-File Report 95-479) is a teacher's guide to two U.S. Geological Survey maps that show gravity and magnetic data in contour form superimposed on a LANDSAT satellite image of the San Francisco Bay area.