GPS constraints on vertical crustal motion in the northern Basin and Range

[1] We estimated vertical velocities using an array of 12 continuous GPS stations forming part of the PBO NUCLEUS network. We analyzed data spanning the period 1996 through 2006. The array has an aperture ∼400 km and crosses a major active intracontinental normal fault system in the northern Basin and Range province. The root-mean-square (RMS) of vertical rates relative to a local “no net vertical” frame is 0.3 mm/yr, indicating high relative rate precision. The RMS difference between rates based on Δt ≤ 7-year sub-strands of the total data set and the full ∼10-year rate estimates varies as 2.4 Δt^−1.3 mm/yr. The net vertical rate observed across the greater Wasatch fault zone is consistent with the predictions of elastic half-space dislocation models only when the deep slipping part of the fault has very shallow dip (<30°).