Original paper
Modelling the Earth's Deep Interior
Dziewonski, Adam M.
Global Tectonics and Metallogeny Volume 4 Number 1-2 (1991), p. 53 - 58
10 references
published: Jan 1, 1991
ArtNo. ESP136000401003, Price: 19.00 €
Abstract
The pace of progress in seismology has recently quickened. Thirty years elapsed between the discovery of the fluid core by Oldham in 1906 and the discovery of the inner core by Lehmann; it took a further 35 years for a rigorous proof that the inner core is solid. Only three years separate the first three dimensional maps of the upper mantle and the presentation of two independent results on the aspherical structure of the inner core. Studies of the Earth's aspherical structure have now matured to the point where the results can be confirmed by independent techniques, and where important conclusions can be drawn by the intercomparison of different models. The primary reason for this rapid development was the accumulation of a sufficient quantity of high quality digital data from two global networks that began operation in the mid-70's and achieved their full strength by about 1980. Theoretical developments during the last three decades provided the framework of formal analysis and the availability of computers, including supercomputers, make feasible the handling of immense amounts of data and the large scale calculations necessary in three dimensional problems. If the internal properties of the Earth were spherically symmetric our planet would be tectonically dead. Both short (earthquakes, volcanoes) and long time scale (mountain building, seafloor spreading) observations indicate that this is not the case. This dynamic behavior must be driven by lateral differences in temperature and density. Unfortunately, the internal distribution of these parameters cannot be uniquely inferred from observations at the surface.
Keywords
Earth's Deep Interior • seismology • earthquakes • volcanoes