Deformation in the Jura Mountains (France): First results from semi-permanent GPS measurements

New GPS estimates of relative motion across the Jura Mountain Belt with respect to the Eurasian Plate indicate less than 1 mm/yr of convergence, considerably less than previous estimates. Velocity uncertainties have been evaluated by several methods and range from 0.2 to 0.5 mm/yr for the semi-permanent stations. The major, statistically-significant strain feature inferred by the Jura GPS measurements is along-arc extension, compatible with tectonic studies. That the detected deformation is small in magnitude highlights two important issues: previous estimates are over-stated and that the approach of using semi-permanent GPS installations is capable of detecting small tectonic signals. Using the upper bound as the rate of convergence, we estimate that this would generate an earthquake of magnitude 5-5.5 every 15 to 75 yr.