News & Press
New Global Tectonic Activity Map of Earth ProducedCynthia O'Carroll
Nov. 5, 1999
RELEASE NO: 99-116
NEW GLOBAL DIGITAL TECTONIC ACTIVITY MAP OF THE EARTH PRODUCED
NASA scientists have developed a new digital tectonic activity map of the Earth that pinpoints the geologically and volcanically active features of the entire planet over the last one million years. The map (actually a series of six color maps with the same scale and projection) combines ground- and space -based information to show the Earth's currently active large-scale features, including major faults, earthquakes and volcanoes.
Most global geological maps are "plate maps" where the emphasis is on defining the plate boundaries on the Earth's crust and the current seismic or volcanic activity. However, a tectonic map portrays the broad architecture of the Earths crust and includes the current and past activity of all the geological structures.
Since the Digital Tectonic Activity Map (DTAM) expresses tectonic activity not just at the plate boundaries but at the intra-plate level (within the plate region), it provides researchers and educators with a more realistic picture of the Earths crustal dynamics which may lead to a better understanding of our volatile Earth.
"The DTAM is different from the 'plate maps' common in geology textbooks because it shows not only well-recognized features such as the Pacific Plate, but it also shows broad zones of earthquake and volcanic activity that are not simply plate boundary features. For example, the map shows a belt of earthquakes off the coast of Norway, not usually considered a seismic zone or a plate boundary. These earthquakes may outline a previously unmapped fault zone," according to the principal investigator, Paul Lowman, of NASAs Goddard Space Flight Center, Greenbelt, Md.
The digital map also shows the motions of NASA space geodesy stations around the world. Using radio telescopes, NASA and cooperating scientists in other countries can measure intercontinental distances with an accuracy of half an inch (about one centimeter). The data shows, for example that the Hawaiian Islands are moving toward Japan at about three inches a year (about seven centimeters). The map also shows rates of sea-floor spreading and zones of volcanism where the oceanic crust is moving apart at the mid-ocean ridges.
The new digital tectonic map also provides a tool for researchers concerned with monitoring and predicting natural hazards such as earthquakes and volcanic eruptions worldwide. The digital map is published in the November issue of the Journal of Geoscience Education. The map may be viewed at the following web site: http://denali.gsfc.nasa.gov/dtam/
Based partly on spacecraft data, including orbital photographs, the map was generated primarily by computer techniques using publicly available data and commercial software. The data sources used include Landsat spacecraft, hand-held astronaut photography and ocean topography data from other NASA spacecraft that use radar altimetry to gather sea surface measurements.
"The combination of vastly increased knowledge of the Earth from space-related and conventional studies, with new data-handling techniques, has produced a new view of the Earth's tectonic and volcanic activity," stated Lowman.
Other researchers involved with this project are Jacob Yates, Penny Masuoka, Brian Montgomery and Jay OLeary, all scientists from Goddard. A geology student, Demetra Salisbury from the University of Arkansas, Fayetteville, contributed to the project.
For more information see this web site: http://denali.gsfc.nasa.gov
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