Plate tectonics is the scientific theory that Earth's lithosphere comprises a number of large tectonic plates, which have been slowly moving since about 3.4 billion years ago. The model builds on the concept of continental drift, an idea developed during the first decades of the 20th century. Plate tectonics came to be accepted by geoscientists after seafloor spreading was validated in the mid-to-late 1960s.
A lithosphere is the rigid, outermost rocky shell of a terrestrial planet or natural satellite. On Earth, it is composed of the crust and the lithospheric mantle, the topmost portion of the upper mantle that behaves elastically on time scales of up to thousands of years or more. The crust and upper mantle are distinguished on the basis of chemistry and mineralogy.
The asthenosphere is the mechanically weak and ductile region of the upper mantle of Earth. It lies below the lithosphere, at a depth between ~80 and 200 km below the surface, and extends as deep as 700 km (430 mi). However, the lower boundary of the asthenosphere is not well defined.
Subduction is a geological process in which the oceanic lithosphere and some continental lithosphere is recycled into the Earth's mantle at convergent boundaries. Where the oceanic lithosphere of a tectonic plate converges with the less dense lithosphere of a second plate, the heavier plate dives beneath the second plate and sinks into the mantle. A region where this process occurs is known as a subduction zone, and its surface expression is known as an arc-trench complex. The process of subduction has created most of the Earth's continental crust. Rates of subduction are typically measured in centimeters per year, with rates of convergence as high as 11 cm/year.
The Mohorovičić discontinuity – usually called the Moho discontinuity, Moho boundary, or just Moho – is the boundary between the crust and the mantle of Earth. It is defined by the distinct change in velocity of seismic waves as they pass through changing densities of rock.
Tectonophysics, a branch of geophysics, is the study of the physical processes that underlie tectonic deformation. This includes measurement or calculation of the stress- and strain fields on Earth’s surface and the rheologies of the crust, mantle, lithosphere and asthenosphere.
A craton is an old and stable part of the continental lithosphere, which consists of Earth's two topmost layers, the crust and the uppermost mantle. Having often survived cycles of merging and rifting of continents, cratons are generally found in the interiors of tectonic plates; the exceptions occur where geologically recent rifting events have separated cratons and created passive margins along their edges. Cratons are characteristically composed of ancient crystalline basement rock, which may be covered by younger sedimentary rock. They have a thick crust and deep lithospheric roots that extend as much as several hundred kilometres into Earth's mantle.
The European Geosciences Union (EGU) is a non-profit international union in the fields of Earth, planetary, and space sciences whose vision is to "realise a sustainable and just future for humanity and for the planet." The organisation has headquarters in Munich, Germany. Membership is open to individuals who are professionally engaged in or associated with these fields and related studies, including students, early career scientists and retired seniors.
Earth science or geoscience includes all fields of natural science related to the planet Earth. This is a branch of science dealing with the physical, chemical, and biological complex constitutions and synergistic linkages of Earth's four spheres: the biosphere, hydrosphere/cryosphere, atmosphere, and geosphere. Earth science can be considered to be a branch of planetary science but with a much older history.
Peter Alfred Ziegler was a Swiss geologist, who made contributions to the understanding of the geological evolution of Europe and the North Atlantic borderlands, of intraplate tectonics and of plate tectonic controls on the evolution and hydrocarbon potential of sedimentary basins. Ziegler's career consists of 33 years as exploration geologist with the petroleum industry, 30 of which with Shell, and 20 years of university teaching and research.
Large low-shear-velocity provinces (LLSVPs), also called large low-velocity provinces (LLVPs) or superplumes, are characteristic structures of parts of the lowermost mantle, the region surrounding the outer core deep inside the Earth. These provinces are characterized by slow shear wave velocities and were discovered by seismic tomography of deep Earth. There are two main provinces: the African LLSVP and the Pacific LLSVP, both extending laterally for thousands of kilometers and possibly up to 1,000 kilometres vertically from the core–mantle boundary. These have been named Tuzo and Jason respectively, after Tuzo Wilson and W. Jason Morgan, two geologists acclaimed in the field of plate tectonics. The Pacific LLSVP is 3,000 kilometers across and underlies four hotspots on Earth's crust that suggest multiple mantle plumes underneath. These zones represent around 8% of the volume of the mantle, or 6% of the entire Earth.
The lithosphere–asthenosphere boundary represents a mechanical difference between layers in Earth's inner structure. Earth's inner structure can be described both chemically and mechanically. The lithosphere–asthenosphere boundary lies between Earth's cooler, rigid lithosphere and the warmer, ductile asthenosphere. The actual depth of the boundary is still a topic of debate and study, although it is known to vary according to the environment.
David Gubbins is a British former geophysicist concerned with the mechanism of the Earth's magnetic field and theoretical geophysics. He is Emeritus Professor of Earth Sciences at Leeds University.
Effective elastic thickness of the lithosphere is the estimated thickness of the elastic plate to substitute for lithosphere in order to investigate observed deformation. It is also presented as Te.
Alik Ismail-Zadeh is a mathematical geophysicist known for his contribution to computational geodynamics and natural hazard studies, pioneering work on data assimilation in geodynamics as well as for outstanding service to the Earth and space science community. He is Senior Research Fellow at the Karlsruhe Institute of Technology in Germany.
Anne Davaille is a French geophysicist and director of research at the CNRS, France in the field of Earth Sciences. Davaille is known for her innovative experiments using thermochemical convection in fluids to simulate the mantles of planets. She uses these experiments to analyze fluid mechanics that create a new understanding of convective regimes in Earth and other planets.
Karen Fischer is an American seismologist known for her research on the structure of Earth's mantle, its lithosphere, and how subduction zones change over geologic history.
Hans Thybo is a Danish geophysicist and geologist. He is President of International Lithosphere Program since 2017.
Richard G. Gordon is an American geophysicist, known for his research on global tectonics, including global plate motions and palaeomagnetism. He is noteworthy for leading two global plate motion projects: NUVEL and MORVEL. In the geosciences, NUVEL and MORVEL are standard models for global plate motions.
Susanna Zerbini is an Italian geophysicist, geodesist, and geodynamicist. She is known as a pioneer in developing and applying satellite geodesy for research in geodynamics and Earth system sciences.
