Magnetic anomaly maps provide insight into the subsurface structure and composition of the Earth's crust. Anomalies trending parallel to the isochrons (lines of equal age) in the oceans reveal the temporal evolution of oceanic crust. Magnetic maps are widely used in the geological sciences and in
resource exploration. Furthermore, the global magnetic map is useful in science education to illustrate various aspects of Earth evolution such as plate tectonics and crustal interaction with the deep mantle. Distinct patterns and magnetic signatures can be attributed to the formation (seafloor spreading) and destruction (subduction zones) of oceanic crust, the formation of
continental crust by accretion of various terranes to cratonic areas and large scale volcanism (both on continents and oceans).
EMAG2 is a significant update over our first global magnetic anomaly grid,
EMAG3, which provided the base grid for the World Digital Magnetic Anomaly Map of the
Commission of the World Geological Map.
As reflected in the name the resolution has been improved from 3 arc minute to 2 arc minute and the altitude has been reduced from 5 km to 4 km above geoid.
Additional grid and trackline data have been included, both over land and the oceans. Interpolation between sparse tracklines in the oceans was improved by directional gridding and extrapolation, based on an
oceanic crustal age model .
The longest wavelengths (larger than 330 km) were replaced with the latest
CHAMP lithospheric field model
MF6.