Digital Tectonic Activity Map (DTAM)
Abstract: This paper presents two Robinson Projection versions of a map showing tectonic and volcanic activity of the geologic present, defined as the last one million years. One version is a shaded relief base map computer-generated from a National Geophysical Data Center digital elevation model, the other a schematic version showing in addition the distribution of continental and oceanic crust. Volcanic features active within the last one million years were generalized from Smithsonian Institution Holocene volcanism compilations, supplemented by geologic maps and orbital photography. Global seismicity (1963-1998) was digitally compiled from National Geophysical Data Center and U.S. Geological Survey databases.Horizontal motions of Very Long Baseline Interferometry (VLBI) space geodesy stations were compiled from Goddard Space Flight Center data. Sources for all data are given, including the Internet URLs. The maps are all in the public domain and may be freely reproduced if the source is credited. Tectonic implications are briefly discussed. The maps show that the Earth's crust can not be realistically described in terms of a small number of rigid plates; that the Appalachians and Urals may still be active; that some of the most intense seismic activity (western Europe) is between two of the most slowly-moving plates (African and Eurasian); and that space geodesy does not necessarily measure plate motion relative to the mantle.
Lowman, P., Yates, J., Masuoka, P., Montgomery, B., O'Leary, J., & Salisbury, D. "A Digital Tectonic Activity Map of the Earth" Journ. Geoscience Ed., vol. 47, no. 5, p.428-437. Nov. 1999.