• Home
  • NASA
  • Satellite Geodesy and Geodynamics Systems Group
  • Donald F. Argus
Donald F. Argus

Donald F. Argus
NASA · Satellite Geodesy and Geodynamics Systems Group

About

106
Publications
35,201
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
17,756
Citations

Publications

Publications (106)
Article
Full-text available
Plain Language Summary Hydrogeodesy is a relatively new discipline within the earth sciences that analyzes the storage and movement of water at or near Earth's surface using measurements of Earth's shape, orientation, and gravitational field. In this paper, we review the current state of hydrogeodesy, focusing on the use of Global Positioning Syste...
Article
Full-text available
We distinguish between two models of solid Earth's viscoelastic response to unloading of the Laurentide ice sheet over the past 26,000 years. The upper mantle viscosity in both models is 0.5 × 10²¹ Pa s. The viscosity of the top 500 km of the lower mantle (670–1,170 km) in model L17 is 13 × 10²¹ Pa s, eight times larger than the value of 1.6 × 10²¹...
Article
Full-text available
The Global Positioning System (GPS) has revolutionized the ability to monitor Earth-system processes, including Earth’s water cycle. Several analysis centers process GPS data to estimate ground-antenna positions at daily temporal resolution. Differences in processing strategies can lead to inconsistencies in coordinate-position estimates and theref...
Article
Full-text available
Great Lakes water levels rose 0.7–1.5 m from 2013 to 2019, increasing surface water volume by 285 km³. Solid Earth's elastic response to the increased mass load is nearly known: The Great Lakes floor fell 8–23 mm, and the adjacent land fell 3–14 mm. Correcting GPS measurements for this predicted elastic loading (1) straightens position‐time series,...
Article
Full-text available
GPS time series of vertical displacement include the elastic response of the Earth to a combination of regional and local loading signals arising from hydrologic mass transfer. The regional loading, controlled by seasonal, synoptic precipitation patterns, dominates the displacement of individual stations and is highly correlated among stations with...
Article
Full-text available
On 26 August 2017, Hurricane Harvey struck the Gulf Coast as a category four cyclone depositing ~95 km3 of water, making it the wettest cyclone in U.S. History: Water left in Harvey's wake should cause elastic loading and subsidence of Earth's crust, and uplift as it drains into the ocean and evaporates. To track daily changes of transient water...
Article
Geodetic data show that the Los Angeles metropolitan area is undergoing 8–9 mm/year of north-south tectonic shortening associated with the Big Bend of the San Andreas Fault. This shortening has been linked to multiple damaging twentieth century thrust earthquakes as well as possible Mw ≥ 7.0 Holocene thrust events beneath central Los Angeles. To be...
Article
Full-text available
The accelerated rate of decline in groundwater levels across California's Central Valley results from overdrafting and low rates of natural recharge and is exacerbated by droughts. The lack of observations with an adequate spatiotemporal resolution to constrain the evolution of groundwater resources poses severe challenges to water management effor...
Article
The most recently published model of the glacial isostatic adjustment process in the ICE-NG (VMX) sequence from the University of Toronto, denoted ICE-6G_C (VM5a), was originally developed to degree and order 256 in spherical harmonics and has been shown to provide accurate fits to a voluminous data base of GPS observations from North America, Eura...
Article
Full-text available
Drought struck California during 7 of the 9 years from 2007 through 2015, reducing the state's available water resources. Pumping of Central Valley groundwater has produced spectacular land subsidence. Uplift of the adjacent Sierra Nevada mountains has been proposed to be either tectonic uplift or solid Earth's elastic response to unloading of Cent...
Article
Full-text available
In recent decades, high groundwater extraction rates, often coincident with periods of severe drought, result in the widespread decline of water levels. Overexploitation of aquifers also causes land subsidence, which poses a severe threat to infrastructure. Tucson, Arizona experiences land subsidence coupled with the depletion of groundwater, a cri...
Article
Quantitative approaches to assess the complexity of groundwater drought are hindered by the lack of direct observations of groundwater over space and time. Here, we present an approach to evaluate groundwater drought occurrence based on observations from NASA's Gravity Recovery and Climate Experiment (GRACE) satellite mission. Normalized GRACE-deri...
Article
Full-text available
The second reprocessing of all GPS data gathered by the Analysis Centers of IGS was conducted in late 2013 using the latest models and methodologies. Improved models of antenna phase center variations and solar radiation pressure in JPL’s reanalysis are expected to significantly reduce errors. In an earlier work, JPL estimates of position time seri...
Article
In the context of the 2014 realization of the International Terrestrial Reference Frame (ITRF2014), the International DORIS Service (IDS) has delivered to the IERS a set of 1140 weekly SINEX files including station coordinates and Earth orientation parameters, covering the time period from 1993.0 to 2015.0. From this set of weekly SINEX files, the...
Chapter
While accuracy of tracking station coordinates is of key importance for Precise Orbit Determination (POD) for altimeter satellites, reliability and operationality are also of great concern. In particular, while recent ITRF realizations should be the most accurate at the time of their computation, they cannot be directly used by the POD groups for o...
Article
Full-text available
The Global Positioning System (GPS) measures elastic ground loading deformation in response to hydrological mass variations on or near Earth's surface. We present a time series of change in terrestrial water storage as a function of position in Washington and Oregon estimated using GPS measurements of vertical displacement of Earth's surface. The d...
Article
Full-text available
A new model of the last deglaciation event of the Late Quaternary ice-age is here described and denoted ICE-6G_C (VM5a). It differs from previously published models in this sequence in that it has been explicitly refined by applying all of the available global positioning system (GPS) measurements of vertical motion of the crust that may be brought...
Article
Full-text available
A new model of the deglaciation history of Antarctica over the past 25 kyr has been developed, which we refer to herein as ICE-6G_C (VM5a). This revision of its predecessor ICE-5G (VM2) has been constrained to fit all available geological and geodetic observations, consisting of: (1) the present day uplift rates at 42 sites estimated from GPS measu...
Article
Full-text available
GPS is accurately recording vertical motion of Earth's surface in elastic response to seasonal changes in surface water storage in California. California's mountains subside up to 12 mm in the fall and winter due to the load of snow and rain, then rise an identical amount in the spring and summer when the snow melts, the rain runs off, and soil moi...
Article
Full-text available
Ideally, the origin of the Terrestrial Reference Frame (TRF) is defined as the center of mass of the whole Earth system, the time evolution of its orientation is such that no global net rotation of the whole Earth’s surface is possible and the TRF scale is specified through the adoption of some physical constants and time-scale. These parameters ne...
Article
[1] We find seasonal horizontal crustal motions observed by GPS positioning in elastic response to heavy rainfall in the Amazon Basin and to monsoons in Southeast Asia to be consistent with those inferred from Gravity Recovery and Climate Experiment (GRACE) gravity observations of water mass loading. Solid Earth moves toward the Amazon during heavy...
Article
Due to its specific geographical location as well as its geodetic equipment (DORIS, GNSS, microwave transponder and tide gauges), the Gavdos station in Crete, Greece is one of the very few sites around the world used for satellite altimetry calibration. To investigate the quality of the Gavdos geodetic coordinates and velocities, we analyzed and co...
Article
Full-text available
We describe the most recent refinement of the Toronto model of glacial isostatic adjustment (GIA) process, a refinement that has been achieved by bringing to bear the totality of the available GPS measurements of vertical motion of the crust from all of the continents from which significant land ice cover was lost during the most recent glacial-int...
Article
Full-text available
1] Using spectral analysis and data decimation, we estimate the uncertainty in the velocity between the cumulative mass center of Earth (CM) and geodetic sites on Earth's surface. Knowing this velocity is crucial for evaluating space geodetic observations of continental uplift and subsidence in terms of postglacial rebound and sea level rise. We fi...
Data
Full-text available
1] NNR‐MORVEL56, which is a set of angular velocities of 56 plates relative to the unique reference frame in which there is no net rotation of the lithosphere, is determined. The relative angular velocities of 25 plates constitute the MORVEL set of geologically current relative plate angular velocities; the relative angular velocities of the other...
Article
Full-text available
Using GPS observations from 1996 to 2011, we constrain postglacial rebound in Antarctica. Sites in the Ellsworth mountains, West Antarctica, are rising at ≈5±4 mm/yr (95% confidence limits), as in the postglacial rebound model of Peltier, but ±10 mm/yr slower than in the model of Ivins and James. Therefore significant ice loss from the Ellsworth mo...
Article
Full-text available
We present several new global sets of angular velocities of the plates relative to the deeper mantle. A starting point for our estimate of plate motion relative to the hotspots is HS3, a hotspot data set developed by Gripp & Gordon [2002], which consists of two volcanic propagation rates and eleven segment trends from the Pacific, Nazca, South Amer...
Article
Estimates of plate velocities from geodesy depend on the velocity of Earth's center, which is the point relative to which geodetic site motions are described. In GEODVEL [Argus et al. 2010], a set of estimates of the velocities of 11 plates from space observations from GPS, SLR, VLBI, and DORIS over 25 yr, we define Earth's center to be (CE) the ma...
Article
Full-text available
We determine NNR-MORVEL56, a set of estimates of the velocities of 56 plates relative to the reference frame yielding no net rotation of the plates. We furthermore determine the full 168 by 168 covariance matrix describing uncertainties in the 56 velocities. 25 plate velocities are from geologically current plate motion model MORVEL [DeMets et al....
Article
Estimates of plate motions relative to the hotspots are useful in investigations of plate driving forces, motion between hotspots, and in estimating the net-rotation of the lithosphere. HS3B-MORVEL is a new set of angular velocities of the plates relative to the hotspots. In HS3B-MORVEL, relative plate angular velocities are constrained to be consi...
Article
Full-text available
We describe best-fitting angular velocities and MORVEL, a new closure-enforced set of angular velocities for the geologically current motions of 25 tectonic plates that collectively occupy 97 per cent of Earth's surface. Seafloor spreading rates and fault azimuths are used to determine the motions of 19 plates bordered by mid-ocean ridges, includin...
Article
Using global positioning system, very long baseline interferometry, satellite laser ranging and Doppler Orbitography and Radiopositioning Integrated by Satellite observations, including the Canadian Base Network and Fennoscandian BIFROST array, we constrain, in models of postglacial rebound, the thickness of the ice sheets as a function of position...
Article
Using space geodetic observations from four techniques (GPS, VLBI, SLR and DORIS), we simultaneously estimate the angular velocities of 11 major plates and the velocity of Earth's centre. We call this set of relative plate angular velocities GEODVEL (for GEODesy VELocity). Plate angular velocities depend on the estimate of the velocity of Earth's c...
Article
We review some of the evidence for significant changes in plate motion during the past 25 Ma. We will review plate motions estimated over the past 0.78 to 3.2 Ma in the MORVEL set of relative plate angular velocities [DeMets, Gordon, and Argus, 2009], which are derived mainly from spreading rates from marine magnetic anomalies and from the azimuths...
Article
Models of the evolving paleo-topography of the continents and paleo-bathymetry of the oceans, together with the evolving ``masks'' of the land-sea and surface albedo distributions, are required inputs for the application of modern coupled climate models in the reconstruction of past climate conditions. Previous reconstructions in the ICE-NG (VMX) s...
Article
To test whether plate velocities averaged over the past two decades equal those averaged over the past 1 to 3 million years, we compare the angular velocities in model GEODVEL against those in MORVEL. GEODVEL is determined from four space geodetic techniques, GPS, SLR, VLBI, and DORIS. In GEODVEL we assume Earth's center to be (CE) the mass center...
Article
We are using observations from five space techniques (VLBI, SLR, GPS, DORIS, and GRACE) to (1) determine the character of Earth's viscous response to unloading of the ice sheets 5 to 20 thousand years ago, and (2) constrain models of postglacial rebound determined primarily from Holocene estimates of relative sea level and geophysical observations...
Article
Full-text available
MORVEL is a new global set of closure-enforced relative angular velocities for the geologically recent motions of 20 tectonic plates. It is determined from a greatly expanded data set consisting of 1696 seafloor spreading rates, 163 transform fault azimuths, and 56 earthquake slip directions from 29 plate boundaries, and 381 GPS station velocities...
Article
The existence of a distinct Capricorn component plate within the composite Indo-Australian plate has previously been questioned. If there is no Capricorn plate, the global positioning system site at Bangalore (on the Indian plate) is predicted to move relative to the Australian plate at a velocity of 10 mm yr(-1). If there is a distinct Capricorn p...
Article
Regional reference frames fixed to the stable part of a tectonic plate are often required for national spatial reference systems and to facilitate geophysical interpretation and inter-comparison of geodetic solutions of crustal motions. In 2003, the Stable North American Reference Frame (SNARF) Working Group was established under the auspices of UN...
Article
Estimates of site velocity are determined relative to Earth's center; therefore the velocity of Earth's center is fundamental to geodesy and geoscience. I present and compare different means by which to define Earth's center. Earth's center can be defined to be either (CM) the mass center of Earth, oceans, and atmopshere, (CE) the mass center of so...
Article
Estimates of site velocity in International Terrestrial Reference Frame 2005 [Altamimi et al. 2007] may, we propose, be transformed into a reference frame in which the North America plate is fixed using: Translation 1.9 millimeters per year toward 82.6S 121.8E Rotation 0.205 degrees per million years CCW about 0.3N 96.6E Resulting estimates of vert...
Article
The characters in Jules Vernes' science-fiction classic of 1864 A Journey to the Centre of the Earth encounter raging waters, erupting volcanoes and giant dinosaurs as they travel deep underground. In truth, even if someone managed to cross our planet's molten core, which begins halfway down from the Earth's surface, the centre of the planet is so...
Article
Full-text available
Previously, we estimated the angular velocity of the Nubian plate relative to the Somalian plate from an updated set of spreading rates and transform fault azimuths. We found that the Nubia-Somalia plate boundary intersects the Southwest Indian Ridge (SWIR) between ≈26°E and ≈32°E if both the Nubian and Somalian plates are rigid and if the boundary...
Article
Full-text available
Earth's centre is fundamental to geodesy and geoscience because motions of sites on the surface are estimated relative to it. International Terrestrial Reference Frames ITRF2000 and ITRF2005 are defined by the centre of mass of Earth's system (CM), consisting of solid Earth, the ice sheets, the oceans, and the atmosphere. Satellite LAGEOS rotates a...
Article
Full-text available
Starting early in 2005, the positions of GPS stations in the San Gabriel valley region of southern California showed statistically significant departures from their previous behavior. Station LONG moved up by about 47 mm, and nearby stations moved away from LONG by about 10 mm. These changes began during an extremely rainy season in southern Califo...
Article
We are in the process of merging the capabilities of three NASA-funded projects under the umbrella of the NASA Access Project, "Modeling and On-the-fly Solutions for Solid Earth Sciences (MOSES)" to facilitate data mining and modeling of rapidly expanding multi-disciplinary geoscience data sets. (1) The SCIGN- REASoN project is focused on the combi...
Article
To quantify how long an InSAR mission must be to resolve plate boundary deformation and interseismic strain accumulation, we assess InSAR accuracy. Lateral variations in troposphere delay are the main error source in InSAR range. SCIGN GPS estimates of troposphere delay in southern California show the error to increase with lateral distance [Emards...
Article
According to the tenets of plate tectonics, a transform fault is a strike-slip fault along which neither convergence nor divergence occurs. Analysis of global plate motion data indicates that the only true transform faults are the strike-slip faults that offset segments of mid-ocean ridges. Thus, many of Earth's major strike-slip fault systems are...
Article
Full-text available
We determine the relative angular velocities among eleven major plates using four space geodetic techniques. The data input consist of site motions estimated from 24 years of VLBI, 24 years of SLR, 14 years of GPS, and 12 years of DORIS data. We assign sites to plates on the basis of geology. We let sites move independently of plates if they are su...
Article
Since the publication of the widely used NUVEL-1 and NUVEL-1A set of angular velocities in 1990 and 1994, a variety of systematic biases in subsets of their underlying data and potential improvements in the modeling assumptions have been reported. In addition, many new magnetic and multibeam surveys of the mid-ocean ridge system have been published...
Article
To study the viscous response of the earth to the unloading of the late Pleistocene ice sheets and, to a lesser extent, the elastic response of the earth to current changes in ice sheet mass, we integrate geodetic observations from VLBI over 24 years, from SLR over 23 years, from DORIS over 12 years, and from GPS over 11 years. The excellent geodet...
Article
A new analysis of geologically current plate motion across the Southwest Indian ridge (SWIR) and of the current location of the Nubia-Antarctica-Somalia triple junction is presented. Spreading rates averaged over the past 3.2 Myr are estimated from 103 well-distributed, nearly ridge-perpendicular profiles that cross the SWIR. All available bathymet...
Article
Full-text available
We use global positioning system (GPS) geodesy and synthetic aperture radar (SAR) interferometry to distinguish between interseismic strain accumulation and anthropogenic motion in metropolitan Los Angeles. We establish a relationship between horizontal and vertical seasonal oscillations of the Santa Ana aquifer, use this relationship to infer cumu...
Article
Global plate motion models such as NUVEL-1 provide rigorous tests of the assumption of plate rigidity and appear, at first glance, to strongly validate that assumption. But the complex interactions of the plate circuits in such global models can hide important inconsistencies. Here we make a straighforward comparison of Pacific-North America motion...
Article
Estimates of the motion of the spin axis over the past century either neglect plate motion or are relative to the mean lithosphere. To understand the response of the spin axis to mass changes, it is more useful to estimate spin axis motion relative to the hotspots because the hotspots well represent the solid earth. The hotspots originate in the lo...
Article
Full-text available
[1] Detrended crustal deformation measurements from a global network of up to 200 continuous Global Positioning System (GPS) tracking sites are inverted for low degree and order (n, m less than or equal to 6) spherical harmonic series of surface mass variations. An independent geophysical model of the atmosphere, oceans, and water and snow on land...
Article
Full-text available
1] Precise GPS measurements of elastic relative site displacements due to surface mass loading offer important constraints on global surface mass transport. We investigate effects of site distribution and aliasing by higher-degree (n ! 2) loading terms on inversion of GPS data for n = 1 load coefficients and geocenter motion. Covariance and simulat...
Article
The Global Positioning System is a constellation of 24–28 satellites, which can be used to define a global terrestrial reference frame. Daily offsets between a GPS defined frame and ITRF2000 have been estimated using more than a decade of GPS observations from 1990–2001. A linear fit to the full span of data shows agreement between the two frames a...
Article
Solutions from GPS, SLR, VLBI, DORIS, PRARE, and LLR are currently integrated by the ITRF to form a global terrestrial reference frame. The current global standard is ITRF2000. All techniques contribute in some way to the frame but the geocenter is currently defined by SLR alone and the scale is defined by SLR and VLBI. Independent geocenter estima...
Article
GPS observations made from 1994 to 1998 suggest contractional strain to be biggest across the northern half of the metropolis [Argus et al. 1999]. SAR interferometry shows aquifer and oil fields in the metropolis to be rising and falling [Bawden et al. 2001]. If such subsidence and uplift made by man were to accumulate over several years, then hori...
Data
Full-text available
Geodetic results from very long baseline interferometry (VLBI), satellite laser rang-ing (SLR), and the Global Positioning Sys-tem (GPS) are used to estimate angular ve-locities between the Sierran microplate, Pacific plate, and North American plate. The Sierra-Pacific pole of rotation lies near-er to the San Andreas fault than does the Pacific–Nor...
Article
It is now possible to define a global terrestrial reference frame using the GPS satellite constellation. The GPS reference frame has an origin definined as the center of mass about which the satellites orbit. The scale or unit of measurement is the meter which is defined by light travel times from the satellites to receivers on the ground. Orientat...
Article
We integrate results from satellite laser ranging (SLR), very long baseline interferometry (VLBI), and global positioning system (GPS) geodesy to determine GEODVEL, a set of the relative angular velocities of most of the earth's major plates. Using two decades of SLR data and two decades of VLBI data, we determine angular velocities and linear velo...