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Full-Text Articles in Earth Sciences
Decelerating Nazca-South America And Nazca-Pacific Plate Motions, Edmundo O. Norabuena, Timothy H. Dixon, Seth Stein, Christopher G. A. Harrison
Decelerating Nazca-South America And Nazca-Pacific Plate Motions, Edmundo O. Norabuena, Timothy H. Dixon, Seth Stein, Christopher G. A. Harrison
School of Geosciences Faculty and Staff Publications
Space geodetic estimates of the rate of Nazca-South America convergence and Nazca-Pacific spreading averaging over several years show that present day rates are significantly slower than the 3 million year average NUVEL-1A model. The implied rates of deceleration are consistent with longer term trends extending back to at least 20 Ma, about the time of initiation of Andes growth, and may reflect consequences of ongoing subduction and construction of the Andes, e.g., increased friction and viscous drag on the subducted slab as the leading edge of South America thickens.
New Kinematic Models For Pacific-North America Motion From 3 Ma To Present, I: Evidence For Steady Motion And Biases In The Nuvel-1a Model, Charles Demets, Timothy H. Dixon
New Kinematic Models For Pacific-North America Motion From 3 Ma To Present, I: Evidence For Steady Motion And Biases In The Nuvel-1a Model, Charles Demets, Timothy H. Dixon
School of Geosciences Faculty and Staff Publications
We use velocities derived from 2–4.5 years of continuous GPS observations at 21 sites on the Pacific and North American plates along with a subset of the NUVEL-1A data to examine the steadiness of Pacific-North America motion since 3.16 Ma, the transfer of Baja California to the Pacific plate, and the magnitude of biases in the NUVEL-1A estimate of Pacific-North America motion. We find that Pacific-North America motion has remained steady since 3.16 Ma, but at rates significantly faster than predicted by NUVEL-1A. In the vicinity of Baja California, our GPS-derived model and recent seafloor spreading rates in the southern …
Noise In Gps Coordinate Time Series, Ailin Mao, Christopher G.A. Harrison, Timothy H. Dixon
Noise In Gps Coordinate Time Series, Ailin Mao, Christopher G.A. Harrison, Timothy H. Dixon
School of Geosciences Faculty and Staff Publications
We assess the noise characteristics in time series of daily position estimates for 23 globally distributed Global Positioning System (GPS) stations with 3 years of data, using spectral analysis and Maximum Likelihood Estimation. A combination of white noise and flicker noise appears to be the best model for the noise characteristics of all three position components. Both white and flicker noise amplitudes are smallest in the north component and largest in the vertical component. The white noise part of the vertical component is higher for tropical stations (±23° latitude) compared to midlatitude stations. Velocity error in a GPS coordinate time …