Moving mountains: Alps researchers detect a decade of movement
GPS data serves as the basis for a geodetic model of the Alps. Here, a horizontal strain field is derived from the data. Red areas indicate compression; blue indicates lateral spreading. (Image: DGFI-TUM)
Our Earth is constantly on the move, as the current Kilauea eruption dramatically illustrates. But capturing data on small shifts over time isn’t so easy.
A new computer model based on more than a decade of GPS data shows the dynamic movements of the Alps as the mountain range drifts and rises.
In general, the range drifts an average of one-half millimeter and rises 1.8 millimeters every year.
However, there are strong regional variances. In South and East Tyrol, a rotation towards the east is superimposed on the overall movement, while at the same time the mountain range is being compressed. And the rise in height is not identical everywhere, either. While very small in the southern part of the western Alps, it reaches its maximum with a speed of more than 2 millimeters per year in the central Alps at the boundaries of Austria, Switzerland and Italy.
To create the model, researchers at the Technical University of Munich (TUM) German Geodetic Research Institute evaluated measurements made by more than 300 GPS antennas over a period of 12 years, in the German, Austrian, Slovenian, Italian, French and Swiss Alps. Over that time, each of the stations has been making positioning measurements every 15 seconds.
The team’s model makes the movements visible on a comprehensive basis for the first time.
The scientists identified the positions of the measurement stations, accurate down to fractions of a millimeter; many of the stations were set up in the EU project ALPS-GPSQUAKENET and are in part operated by TUM.
Once corrected for snow weight and atmospheric interference, the data show horizontal and vertical shifts as well as lateral spreading and compression at a resolution of 25 kilometers.
Explains Florian Seitz, chair of Geodetic Geodynamics, “The data are a goldmine for geodesy, with its objective of accurately measuring the surface of the Earth and identifying any changes occurring.”
About the Author: Tracy Cozzens
Senior Editor Tracy Cozzens joined GPS World magazine in 2006. She also is editor of GPS World’s newsletters and the sister website Geospatial Solutions. She has worked in government, for non-profits, and in corporate communications, editing a variety of publications for audiences ranging from federal government contractors to teachers.
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