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Abdullah ArRajehi

Bio: Abdullah ArRajehi is an academic researcher from King Abdulaziz City for Science and Technology. The author has contributed to research in topics: Plate tectonics & Slab pull. The author has an hindex of 4, co-authored 4 publications receiving 1589 citations.

Papers
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Journal ArticleDOI
TL;DR: In this article, an elastic block model was developed to constrain present-day plate motions (relative Euler vectors), regional deformation within the interplate zone, and slip rates for major faults.
Abstract: [1] The GPS-derived velocity field (1988–2005) for the zone of interaction of the Arabian, African (Nubian, Somalian), and Eurasian plates indicates counterclockwise rotation of a broad area of the Earth's surface including the Arabian plate, adjacent parts of the Zagros and central Iran, Turkey, and the Aegean/Peloponnesus relative to Eurasia at rates in the range of 20–30 mm/yr. This relatively rapid motion occurs within the framework of the slow-moving (∼5 mm/yr relative motions) Eurasian, Nubian, and Somalian plates. The circulatory pattern of motion increases in rate toward the Hellenic trench system. We develop an elastic block model to constrain present-day plate motions (relative Euler vectors), regional deformation within the interplate zone, and slip rates for major faults. Substantial areas of continental lithosphere within the region of plate interaction show coherent motion with internal deformations below ∼1–2 mm/yr, including central and eastern Anatolia (Turkey), the southwestern Aegean/Peloponnesus, the Lesser Caucasus, and Central Iran. Geodetic slip rates for major block-bounding structures are mostly comparable to geologic rates estimated for the most recent geological period (∼3–5 Myr). We find that the convergence of Arabia with Eurasia is accommodated in large part by lateral transport within the interior part of the collision zone and lithospheric shortening along the Caucasus and Zagros mountain belts around the periphery of the collision zone. In addition, we find that the principal boundary between the westerly moving Anatolian plate and Arabia (East Anatolian fault) is presently characterized by pure left-lateral strike slip with no fault-normal convergence. This implies that “extrusion” is not presently inducing westward motion of Anatolia. On the basis of the observed kinematics, we hypothesize that deformation in the Africa-Arabia-Eurasia collision zone is driven in large part by rollback of the subducting African lithosphere beneath the Hellenic and Cyprus trenches aided by slab pull on the southeastern side of the subducting Arabian plate along the Makran subduction zone. We further suggest that the separation of Arabia from Africa is a response to plate motions induced by active subduction.

1,609 citations

Journal ArticleDOI
TL;DR: In this paper, the authors derived the following relative, geodetic Euler vectors (latitude (°N), longitude(°E), rate (°/Myr, counterclockwise) for Arabia-Nubia (31.7 ± 0.2 mm/yr, left lateral; 0.8-1.5 mm/r, right lateral, increasing from north to south; 1-2 mm /yr extension).
Abstract: [1] Five years of continuously recording GPS observations in the Kingdom of Saudi Arabia together with new continuous and survey-mode GPS observations broadly distributed across the Arabian Peninsula provide the basis for substantially improved estimates of present-day motion and internal deformation of the Arabian plate. We derive the following relative, geodetic Euler vectors (latitude (°N), longitude (°E), rate (°/Myr, counterclockwise)) for Arabia-Nubia (31.7 ± 0.2, 24.6 ± 0.3, 0.37 ± 0.01), Arabia-Somalia (22.0 ± 0.5, 26.2 ± 0.5, 0.40 ± 0.01), Arabia-India (18.0 ± 3.8, 87.6 ± 3.3, 0.07 ± 0.01), Arabia-Sinai (35.7 ± 0.8, 17.1 ± 5.0, 0.15 ± 0.04), and Arabia-Eurasia (27.5 ± 0.1, 17.6 ± 0.3, 0.404 ± 0.004). We use these Euler vectors to estimate present-day stability of the Arabian plate, the rate and direction of extension across the Red Sea and Gulf of Aden, and slip rates along the southern Dead Sea fault south of the Lebanon restraining bend (4.5–4.7 ± 0.2 mm/yr, left lateral; 0.8–1.1 ± 0.3 mm/yr extension) and the Owens fracture zone (3.2–2.5 ± 0.5 mm/yr, right lateral, increasing from north to south; 1–2 mm/yr extension). On a broad scale, the Arabian plate has no resolvable internal deformation (weighted root mean square of residual motions for Arabia equals 0.6 mm/yr), although there is marginally significant evidence for N-S shortening in the Palmyride Mountains, Syria at ≤ 1.5 mm/yr. We show that present-day Arabia plate motion with respect to Eurasia is consistent within uncertainties (i.e., ±10%) with plate tectonic estimates since the early Miocene when Arabia separated from Nubia. We estimate the time of Red Sea and Gulf of Aden rifting from present-day Arabia motion, plate tectonic evidence for a 70% increase in Arabia-Nubia relative motion at 13 Ma, and the width of the Red Sea and Gulf of Aden and find that rifting initiated roughly simultaneously (±2.2 Myr) along the strike of the Red Sea from the Gulf of Suez to the Afar Triple Junction, as well as along the West Gulf of Aden at 24 ± 2.2 Ma. Based on the present kinematics, we hypothesize that the negative buoyancy of the subducted ocean lithosphere beneath the Makran and the Zagros fold-thrust belt is the principle driver of Arabia-Eurasia convergence and that resisting forces associated with Arabia-Eurasia continental collision have had little impact on plate motion.

173 citations

Book ChapterDOI
01 Jan 2015
TL;DR: In this article, the authors use geodetic, plate tectonic, and geologic observations to quantitatively reconstruct the geologic evolution of the Red Sea and Gulf of Aden since separation of Arabia from Africa in the Late Oligocene.
Abstract: We use geodetic, plate tectonic, and geologic observations to quantitatively reconstruct the geologic evolution of the Red Sea and Gulf of Aden since separation of Arabia from Africa in the Late Oligocene. Rifting initiated at 22 ± 3 Ma roughly simultaneously along the full strike of the proto-Red Sea and Gulf of Aden. Rifting began along pre-existing zones of weakness associated with a Pan-African Precambrian collisional suture shortly after the Afro-Arabia Plate was weakened by impingement of the African hot spot (~30 Ma). The initial phase of continental rifting followed a roughly linear trend from the Gulf of Suez in the north, to the Bab-al-Mandab in the south where the Afar Triple Junction (junction of Red Sea, Gulf of Aden, and East African rifts) was located at that time. The initial rate of extension across the rift was roughly half the present-day rate. At 11 ± 2 Ma, the rate of rifting doubled to the present-day rate (24 ± 1 mm/year in the south [~12°N] and 7 ± 1 mm/year in the north [~27°N]) and the configuration of rifting changed in both the northern and southern Red Sea. This time corresponds to the initiation of ocean spreading (i.e., complete severing of the continental lithosphere and intrusion of rift basalts) along the full extent of the Gulf of Aden. The changes in the S Red Sea involved the propagation of the Afar Triple Junction westward to its present location (~11.5°N, 42°E), the transfer of rifting from the S Red Sea (Bab-al-Mandab) to the more N–S-oriented Danakil Depression, and accompanying CCW rotation of the Danakil Block with respect to Africa. In the northern Red Sea, rifting transferred from the Gulf of Suez to the more N–S-oriented Gulf of Aqaba/Dead Sea fault system. The rate of rifting has not changed significantly since that time (i.e., 11 ± 2 Ma). The initiation of rifting at 22 ± 3 Ma corresponds temporally with slowing of Africa–Eurasia convergence by a factor of ~2 and the changes at 11 ± 2 Ma with a second phase of slowing of Africa–Eurasia convergence, while Arabia–Eurasia convergence has remained roughly unchanged since >30 Ma. These observations are consistent with simple models where changes in Africa–Arabia–Eurasia relative plate motions are the fundamental cause of post-Oligocene Middle East and Mediterranean tectonics. Based on the simultaneity between full ocean spreading along the Gulf of Aden and a doubling of the extension rate across the Red Sea, and the change to more N–S-oriented rifting in both the northern and southern Red Sea, we hypothesize that slowing of Africa–Eurasia convergence resulted from a decrease in slab pull on the African Plate across the evolving AR-AF plate boundary.

18 citations

01 Jan 2006
TL;DR: In this article, Reilinger et al. present geodetic constraints on Rupturing of the Continental Lithosphere along the Red Sea along with a map of the region.
Abstract: Geodetic constraints on Rupturing of Continental Lithosphere along the Red Sea Robert Reilinger, Simon McClusky, Abdullah ArRajehi, Salah Mahmoud, Ali Rayan, Woldai Ghebreab, Ghebrebrhan Ogubazghi, and A. Al-Aydrus Department of Earth, Atmospheric, and Planetary Sciences, MIT, Cambridge, MA 02139 USA, King Abdulaziz City for Science and Technology, Riyadh, Kingdom of Saudi Arabia, National Research Institute of Astronomy and Geophysics, Helwan, Cairo, Egypt, Asmara University, Asmara, Eritrea, Faculty of Science, Sana’a University, Yemen

10 citations


Cited by
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Journal ArticleDOI
TL;DR: 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.

2,089 citations

Journal ArticleDOI
TL;DR: In the Himalayan-Tibetan orogen and Turkey-Iranian-Caucasus orogen as mentioned in this paper, the early stages of the orogenic deformation were characterized by shortening in the early stage followed by strike-slip faulting and extension in the late stage.

668 citations

Journal ArticleDOI
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.
Abstract: We present a new global model of plate motions and strain rates in plate boundary zones constrained by horizontal geodetic velocities. This Global Strain Rate Model (GSRM v.2.1) is a vast improvement over its predecessor both in terms of amount of data input as in an increase in spatial model resolution by factor of ∼2.5 in areas with dense data coverage. We determined 6739 velocities from time series of (mostly) continuous GPS measurements; i.e., by far the largest global velocity solution to date. We transformed 15,772 velocities from 233 (mostly) published studies onto our core solution to obtain 22,511 velocities in the same reference frame. Care is taken to not use velocities from stations (or time periods) that are affected by transient phenomena; i.e., this data set consists of velocities best representing the interseismic plate velocity. About 14% of the Earth is allowed to deform in 145,086 deforming grid cells (0.25° longitude by 0.2° latitude in dimension). The remainder of the Earth's surface is modeled as rigid spherical caps representing 50 tectonic plates. For 36 plates we present new GPS-derived angular velocities. For all the plates that can be compared with the most recent geologic plate motion model, we find that the difference in angular velocity is significant. The rigid-body rotations are used as boundary conditions in the strain rate calculations. The strain rate field is modeled using the Haines and Holt method, which uses splines to obtain an self-consistent interpolated velocity gradient tensor field, from which strain rates, vorticity rates, and expected velocities are derived. We also present expected faulting orientations in areas with significant vorticity, and update the no-net rotation reference frame associated with our global velocity gradient field. Finally, we present a global map of recurrence times for Mw=7.5 characteristic earthquakes.

608 citations

Journal ArticleDOI
TL;DR: In this paper, the authors show that only 42% of the post-35 Ma convergence is partitioned by shortening within central Iran, and the current subduction dynamics can be explained by the original lateral difference in the buoyancy of the distal margin.

509 citations

Journal ArticleDOI
TL;DR: In this article, phase diagrams and rock physical properties for a range of bulk compositions appropriate to subduction zones were calculated and merged with global subduction zone rock fluxes to generate a model for global H2O flux to postarc depths.
Abstract: [1] The amount of H2O subducted to postarc depths dictates such disparate factors as the generation of arc and back-arc magmas, the rheology of the mantle wedge and slab, and the global circulation of H2O. Perple_X was used to calculate phase diagrams and rock physical properties for pressures of 0.5–4.0 GPa and temperatures of 300–900°C for a range of bulk compositions appropriate to subduction zones. These data were merged with global subduction zone rock fluxes to generate a model for global H2O flux to postarc depths. For metasomatized igneous rocks, subducted H2O scales with bulk rock K2O in hot slabs. Metasomatized ultramafic rocks behave similarly in cold slabs, but in hot slabs carry no H2O to magma generation depths because they lack K2O. Chert and carbonate are responsible for minimal H2O subduction, whereas clay-rich and terrigenous sediments stabilize several hydrous phases at low temperature, resulting in significant postarc slab H2O flux in cold and hot slabs. Continental crust also subducts much H2O in cold slabs because of the stability of lawsonite and phengite; in hot slabs it is phengite that carries the bulk of this H2O to postarc depth. All told, the postarc flux of H2O in cold slabs is dominated by terrigenous sediment and the igneous lower crust and mantle and is proportional to bulk rock H2O. In contrast, in hot slabs the major contributors of postarc slab H2O are metasomatized volcanic rocks and subducted continental crust, with the amount of postarc slab H2O scaling with K2O. The Andes and Java-Sumatra-Andaman slabs are the principal suppliers of pelagic and terrigenous sediment hosted H2O to postarc depths, respectively. The Chile and Solomon arcs contribute the greatest H2O flux from subducted continental and oceanic forearc, respectively. The Andean arc has the greatest H2O flux provided through subduction of hydrated ocean crust and mantle. No correlation was observed between postarc slab H2O flux and slab seismicity.

410 citations