IGS Stations as Tectonic Tracers and Importance of Local Densification
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Grigory M. Steblov
Russian GPS Data Acquisition and Analysis Center
Geophysical Survey / Russian Academy of Sciences
6 Universitetskiy Prospekt, Building 3
117333 Moscow, Russia

Mikhail Kogan
Lamont-Doherty Earth Observatory
61 Route 9W
Palisades, NY 10964 USA

IGS stations are typically located some thousand kilometers apart from 
each other. A question arises how well such isolated stations can 
represent large-scale plate tectonic motions. We developed local clusters 
of reference GPS stations around each of seven IGS stations spanning 
northern Eurasia from eastern Europe to the Pacific ocean. These clusters 
were re-observed each at least three times since 1996. A reference station 
in Yakutsk (YAKT) was recently converted into a real-time, 1-s sampling 
rate station in the framework of the joint experiment conducted together 
with JPL. We found that in most cases a relative position of the reference 
station with respect to the IGS station does not fluctuate by more than 
2 mm in 3-D, which is compatible with the standard deviation. The permafrost 
condition makes a notable exception.