Geologically current plate motions
Reads0
Chats0
TLDR
MORVEL as discussed by the authors is 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.Abstract:
SUMMARY
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, including all the major plates. Six smaller plates with little or no connection to the mid-ocean ridges are linked to MORVEL with GPS station velocities and azimuthal data. By design, almost no kinematic information is exchanged between the geologically determined and geodetically constrained subsets of the global circuit—MORVEL thus averages motion over geological intervals for all the major plates. Plate geometry changes relative to NUVEL-1A include the incorporation of Nubia, Lwandle and Somalia plates for the former Africa plate, Capricorn, Australia and Macquarie plates for the former Australia plate, and Sur and South America plates for the former South America plate. MORVEL also includes Amur, Philippine Sea, Sundaland and Yangtze plates, making it more useful than NUVEL-1A for studies of deformation in Asia and the western Pacific. Seafloor spreading rates are estimated over the past 0.78 Myr for intermediate and fast spreading centres and since 3.16 Ma for slow and ultraslow spreading centres. Rates are adjusted downward by 0.6–2.6 mm yr−1 to compensate for the several kilometre width of magnetic reversal zones. Nearly all the NUVEL-1A angular velocities differ significantly from the MORVEL angular velocities. The many new data, revised plate geometries, and correction for outward displacement thus significantly modify our knowledge of geologically current plate motions. MORVEL indicates significantly slower 0.78-Myr-average motion across the Nazca–Antarctic and Nazca–Pacific boundaries than does NUVEL-1A, consistent with a progressive slowdown in the eastward component of Nazca plate motion since 3.16 Ma. It also indicates that motions across the Caribbean–North America and Caribbean–South America plate boundaries are twice as fast as given by NUVEL-1A. Summed, least-squares differences between angular velocities estimated from GPS and those for MORVEL, NUVEL-1 and NUVEL-1A are, respectively, 260 per cent larger for NUVEL-1 and 50 per cent larger for NUVEL-1A than for MORVEL, suggesting that MORVEL more accurately describes historically current plate motions. Significant differences between geological and GPS estimates of Nazca plate motion and Arabia–Eurasia and India–Eurasia motion are reduced but not eliminated when using MORVEL instead of NUVEL-1A, possibly indicating that changes have occurred in those plate motions since 3.16 Ma. The MORVEL and GPS estimates of Pacific–North America plate motion in western North America differ by only 2.6 ± 1.7 mm yr−1, ≈25 per cent smaller than for NUVEL-1A. The remaining difference for this plate pair, assuming there are no unrecognized systematic errors and no measurable change in Pacific–North America motion over the past 1–3 Myr, indicates deformation of one or more plates in the global circuit. Tests for closure of six three-plate circuits indicate that two, Pacific–Cocos–Nazca and Sur–Nubia–Antarctic, fail closure, with respective linear velocities of non-closure of 14 ± 5 and 3 ± 1 mm yr−1 (95 per cent confidence limits) at their triple junctions. We conclude that the rigid plate approximation continues to be tremendously useful, but—absent any unrecognized systematic errors—the plates deform measurably, possibly by thermal contraction and wide plate boundaries with deformation rates near or beneath the level of noise in plate kinematic data.read more
Citations
More filters
Journal ArticleDOI
Global continental and ocean basin reconstructions since 200 Ma
Maria Seton,Ralph Müller,Sabin Zahirovic,Carmen Gaina,Trond H. Torsvik,Grace E. Shephard,A.S. Talsma,Michael Gurnis,M. Turner,Stefan Maus,Michael T. Chandler +10 more
TL;DR: In this paper, a new type of global plate motion model consisting of a set of continuously-closing topological plate polygons with associated plate boundaries and plate velocities since the break-up of the supercontinent Pangea is presented.
Journal Article
Digital isochrons of the world's ocean floor
TL;DR: In this article, a digital age grid of the ocean floor with a grid node interval of 6 arc min using a self-consistent set of global isochrons and associated plate reconstruction poles was created.
Journal ArticleDOI
The 2011 Magnitude 9.0 Tohoku-Oki Earthquake: Mosaicking the Megathrust from Seconds to Centuries
Mark Simons,Sarah E. Minson,Anthony Sladen,Anthony Sladen,F. Ortega,Junle Jiang,Susan Owen,Lingsen Meng,Jean-Paul Ampuero,Shengji Wei,Risheng Chu,Donald V. Helmberger,Hiroo Kanamori,Eric A. Hetland,Angelyn Moore,Frank Webb +15 more
TL;DR: Detailed geophysical measurements reveal features of the 2011 Tohoku-Oki megathrust earthquake and suggest the need to consider the potential for a future large earthquake just south of this event.
Journal ArticleDOI
A geodetic plate motion and Global Strain Rate Model
TL;DR: The Global Strain Rate Model (GSRM v.2.1) as mentioned in this paper is a new global model of plate motions and strain rates in plate boundary zones constrained by horizontal geodetic velocities.
Journal ArticleDOI
Geologically current motion of 56 plates relative to the no-net-rotation reference frame
TL;DR: The NNR-MORVEL56 set of geologically current relative plate angular velocities is derived in this article, which is the first set of angular veloci measured relative to the unique reference frame in which there is no net rotation of the lithosphere.
References
More filters
Journal ArticleDOI
Mid-Atlantic Ridge–Azores hotspot interactions: along-axis migration of a hotspot-derived event of enhanced magmatism 10 to 4 Ma ago
Mathilde Cannat,Anne Briais,Christine Deplus,Javier Escartín,Javier Escartín,J. E. Georgen,Jian Lin,Serguei Mercouriev,Christine Meyzen,Mark R. Muller,Gaud Pouliquen,Aline Rabain,Pedro da Silva +12 more
TL;DR: A recent survey of the Mid-Atlantic Ridge over the southern edge of the Azores Platform shows that two anomalously shallow regions located off-axis on both sides of the ridge are the two flanks of a single rifted volcanic plateau as mentioned in this paper.
Journal ArticleDOI
Statistical tests of additional plate boundaries from plate motion inversions
Seth Stein,Richard G. Gordon +1 more
TL;DR: In this article, the F-ratio test was applied to the results of relative plate motion inversions to determine whether the improvement in fit of the model to the data resulting from the addition of another plate to the model is greater than that expected purely by chance.
Journal ArticleDOI
Viscosity of Oceanic Asthenosphere Inferred from Remote Triggering of Earthquakes
TL;DR: The postseismic stress evolution across the northern Pacific and Arctic basins, calculated from a viscoelastic coupling model with an asthenospheric viscosity of 5 x 10(17) pascal seconds, is consistent with triggering of oceanic intraplate earthquakes, temporal patterns in seismicity at remote plate boundaries, and space-based geodetic measurements of anomalous velocity over an area 7000 by 7000 kilometers square during the 30-year period after the sequence as mentioned in this paper.
Journal ArticleDOI
The Motion and Boundary Between the Capricorn and Australian Plates
J. Y. Royer,Richard G. Gordon +1 more
TL;DR: In this article, it was shown that the Somalian, Antarctic, and Australian plates are inconsistent with the assumption that all three plates are rigid, and that the discrepancy is best explained if the Australian plate contains two component plates.
Journal ArticleDOI
Deformation of the North American plate interior from a decade of continuous GPS measurements
TL;DR: In this paper, a combination of two independent geodetic solutions using data from close to 300 continuous GPS stations covering the central and eastern United States shows that surface deformation in the North American plate interior is best fit by a model that includes rigid rotation of North America with respect to ITRF2000 and a component of strain qualitatively consistent with that expected from glacial isostatic adjustment (GIA).