Basically the range of observable periods (or characteristic time constants) covers 8 orders of magnitude from 1 s to several years. The wide spectrum of geophysical phenomena that are observable with SGs is evident in Figure 15. Characteristics of geophysical phenomena observable by SGs. Phase I of GGP was the period 1997–2003 and we are currently in phase II (2003–07).įigure 15. The coverage in the Southern Hemisphere is still weak, despite the effort of installing stations in Australia, Indonesia, and Antarctica by Japanese colleagues, in South Africa by GFZ Potsdam (Germany), and very recently in South America by BKG (Germany) – the TIGO project. As indicated in Figure 14, GGP stations are sparsely distributed worldwide, with only two regional clusters of instruments, one in Europe and a smaller one in Japan. The groups agreed to provide vertical gravity acceleration data in a standard form, basically untouched raw data decimated to 1 min samples, and sent at the end of every month to a database. It consists of a worldwide network of SGs, currently about 20 instruments, run by independent national groups. In 2003, it changed to become an Inter-Commission Project of International Association of Geodesy (IAG) and reports to Commission 2 (The Gravity Field) and Commission 3 (Earth Rotation and Geodynamics). GGP is an international research effort that was launched as a SEDI (Study of the Earth’s Interior) initiative at the Vienna IUGG General Assembly in 1991. The conclusions are based on recent data on melting in mantle systems with CO 2 and reduced C–O–H fluid, the stability of diamond and carbide phases, and the role of redox conditions in carbon and hydrogen cycles. Hydrocarbon-bearing hydrous melt serves as the liquid component in mantle plumes arising from the CMB. Carbonated or carbonatite melt is the best candidate for the fusible component of the plumes, especially for the upper mantle and transition zone. An important requirement for diapiric motion is stress-induced melting and dissolution–precipitation of fusible components at the front and rear of the plume, respectively. Here we discuss the possible nature and composition of melts in the deep upper and lower mantle, which can enhance material transport under superplumes and hot spots originating from the transition zone or from the core–mantle boundary (CMB) of the Earth. Geodynamic models considering fast mantle upwelling without volatile-bearing components are inapplicable due to high melting temperatures of mantle silicates.
Litasov, Anton Shatskiy, in Magmas Under Pressure, 2018 Abstract The observed volcanism is also a clear expression of this recent geodynamic activity in the Aegean geodynamic zone. All these facts are current elements of this very specific boundary transition zone between the European and the African plates. The recent relief on the land and submarine geomorphologic units also give an image of the complex geodynamics from the long-term point of view. The subducted earth crust parts, the surface and deep earth crust movements (some of them detected by the GPS measurements, another by more complicated non direct techniques) are the other components of these complicated regional geodynamics. The location of the fault structures, and observed seismicity (with its spatial and temporal specific behavior), is an important element of the Aegean zone. They are due to the structures with different orientation and different (extensional, compressional and transform) geodynamic regime. The inner parts of the Aegean subduction zone reflect the complicated structure by different elements and geotectonic units. The suggested geodynamic model reflects almost all the recently observed geodynamic phenomena in the Aegean region. Ranguelov, in Developments in Volcanology, 2005 5. Geodynamic models also include the liquid parts of the Earth in models of the outer core, models of magma generation and movement, and models for flow of aqueous fluids in the upper part of the Earth.ī. Temperature as a function of heat generation, conduction, and movement of material (advection). Rock rheology (relationship between imposed stress and consequent deformation of solid rock) and. Gravity couples to density contrasts to give rise to stress. Some key (but generalized) aspects of geodynamic models are:.
Aspects explored in many geodynamic models include the solid-state convection of the mantle, driven by thermally induced density contrasts the evolution of the magnetic field due to outer core behavior and the elastic and viscous response of the lithosphere during deformation near plate margins. These are usually defined mathematically and solved by computation, although ‘analog’ (scaled) experiments are possible. Geodynamics is the general term for models of the large-scale behavior of the Earth.