Space geodesy validation of the global lithospheric flow

Abstract

Space geodesy data are used to verify whether plates move chaotically or rather follow a sort of tectonic mainstream. While independent lines of geological evidence support the existence of a global ordered flow of plate motions that is westerly polarized, the Terrestrial Reference Frame (TRF) presents limitations in describing absolute plate motions relative to the mantle. For these reasons we jointly estimated a new plate motions model and three different solutions of net lithospheric rotation. Considering the six major plate boundaries and variable source depths of the main Pacific hotspots, we adapted the TRF plate kinematics by global space geodesy to absolute plate motions models with respect to the mantle. All three reconstructions confirm (i) the tectonic mainstream and (ii) the net rotation of the lithosphere. We still do not know the precise trend of this tectonic flow and the velocity of the differential rotation. However, our results show that assuming faster Pacific motions, as the asthenospheric source of the hotspots would allow, the best lithospheric net rotation estimate is 13.4 +/- 0.7 cm yr(-1). This superfast solution seems in contradiction with present knowledge on the lithosphere decoupling, but it matches remarkably better with the geological constraints than those retrieved with slower Pacific motion and net rotation estimates. Assuming faster Pacific motion, it is shown that all plates move orderly 'westward' along the tectonic mainstream at different velocities and the equator of the lithospheric net rotation lies inside the corresponding tectonic mainstream latitude band (approximate to +/- 7 degrees), defined by the 1 sigma confidence intervals

Earth’s rotation variability triggers explosive eruptions in subduction zones

“…When these data show an E-or W-component, the subduction geometry is defined as E-or W-directed, respectively (see Additional file 1). Basically, this simplified criterion gives results comparable with those obtained by Crespi et al (2007) and Cuffaro and Doglioni (2007), concerning the E-and W-directed categories. As an example, the NE-or NNE-directed Indonesian subduction zone falls into the "E" class.…”

“…following or opposing the mantle flow inferred from the net rotation of the lithosphere relative to the underlying mantle (Crespi et al 2007;Cuffaro and Doglioni 2007 and references therein). Due to the irregular morphology of plate boundaries and the undulated mainstream of plate motions, subduction processes can occur with normal or oblique motion directions of sinking slabs, relative to the global mainstream of plates that is "westerly" polarized.…”

“…The trenches are subdivided following the shape of the tectonic equator, described by Crespi et al (2007) or Cuffaro and Doglioni (2007). The shape of the tectonic equator, the lithosphere net rotation main directions and velocities are reported in Additional file 1: Figure S1.…”

Mutual Coupling Between Meteorological Parameters and Secondary Microseisms

“…The arrival delay of the deformation wave from the region of Indonesia was about 4 -10 days, and from South America approximately 10 -25 days. Most of these waves travel along the discontinuities, in the direction from east to west, probably due to the western drift of the lithosphere (Crespi et al 2007). In contrast, the prevailing propagation of these waves after the Tohoku earthquake, in 2011, was observed across the North Pole through the northern and southern Atlantic, thence around the South Pole to the Pacific.…”

Transition from continental collision to tectonic escape? A geophysical perspective on lateral expansion of the northern Tibetan Plateau

“…Here, we incorporate both the Vs structure from surface wave tomography and ρ structure from gravity inversion to the depth of 350 km, and we obtain the gravitational potential energy of the plateau Zhang 2010;Zhang et al 2014). Our results, which are the outcome of a specific synthesis based on the review paper by Zhang et al (2014), suggest that the study of the SW-ward decoupling of the lithosphere relative to the mantle in the framework of the net rotation, also called "westward" drift of the lithosphere (Crespi et al 2007) may contribute to the understanding of the geodynamics of the study area. A relative NE-ward mantle flow sustains the Indian slab and the overlying orogen.…”