Vertical Motion of the Basin and Range, Western United States, from 10 Years of Campaign GPS

An analysis of 10 years of campaign Global Positioning System (GPS) data collected in periodic surveys of the Basin and Range shows that vertical velocity measurement is less precise than horizontal measurements by approximately a factor of 3, and less precise than velocities from continuous GPS sites by a factor of 3-4. To obtain this level of precision, a method for conservatively quantifying uncertainties that takes into account the misfit of velocity data to a constant strain rate model is employed. This method results in a reduction of uncertainties by approximately a factor of 2. Uncertainties in position and velocity, for campaign and continuous sites are compared to results from other groups. Most of the vertical velocities in the Basin and Range are not resolvably different than zero, to 95% confidence. However, collecting sites into sub-networks of 10 sites indicates a marginally significant ~2 mm/yr of vertical motion between 114 ̊ west longitude (up) compared 119 ̊ west longitude (down). The greatest east/west tilting rates are 58.8±14.6 nanoradians per year eastward and 52.4±15.9 nanoradians per year westward on the flanks of an area of relative uplift near 114 ̊ west longitude.