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IUGG XXIV General Assembly July 2-13, 2007 Perugia, Italy
(S) - IASPEI - International Association of Seismology and Physics of the Earth's
Interior
JSS011 Poster presentation 2173
Error analysis of strain rates from GPS measurements based on Monte-
Carlo method
Dr. Shoubiao Zhu
Geophysics Institute of Crustal Dynamics, CEA IASPEI
Yaolin Shi
The strain rates in Chinese continent have been computed from GPS data by many researchers,
resulting in quite different estimates of the strain rates. Moreover, until now, researchers have not
presented the errors of the strain rates yet, which are very important in geodynamics. In order to solve
this problem, we propose the method to calculate the errors of strain rates, computed from GPS vectors
with measurement errors, on the base of Monte Carlo technique. Taken the Qinghai-Tibet plateau as an
example, independent computation of strain rate is repeated for large numbers of times (4000 times in
this research) and the components of strain rates, as well as the errors, are obtained by statistical
theory. The result shows that the errors of strain rates in NS, WE directions and shear components,
respectively, are larger in Himalayas and both in the middle and in the east of the plateau than those in
other places. The distribution of the statistical average strain rates is similar to the one calculated from
the GPS vectors without considering the errors of the GPS observation. In general, the strain rate in
whole Qinghai-Tibet plateau is accurate and stable. Also the result suggests that the errors of the strain
rates computed from GPS measurements are mainly originated from the errors of GPS data. The
accuracy of GPS survey does not meet the requirements for precisely computing the strain rates in the
region where there is a small value of deformation, for example in east China with the relative errors of
strain rates greater than 100%.
Keywords: strain rate field, error analysis, monte carlo method