Global Mapping of the Uppermantle by Surface Wave Tomography

Surface wave tomography compliments detailed body wave studies by providing a global framework for the lateral variability of the uppermantle. In particular the method allows one to map the mantle beneath the lithosphere and to discuss the fate of overridden oceanic plates. Midocean ridges appear to extend to at least 400 km. By contrast, the very high velocities associated with shields are primarily much shallower. The Red Sea-Afar region is a pronounced and deep low-velocity anomaly. A significant uppermantle anomaly has been found in the central Pacific. This "Polynesian Anomaly" is surrounded by hotspots; Hawaii, Tahiti, Samoa and the Caroline Islands. This may be the site of the extensive Cretaceous volanism which generated the plateaus and seamounts in the western Pacific. Anisotropy indicates deep upwellings, >300 km depth, under midocean ridges, the Afar and the Polynesian Anomaly and downwelling under the western Pacific and the northeastern Indian Ocean. The large fast anomaly under the south Atlantic may represent overridden Pacific plate

Neutrino mixing and masses from long baseline and atmospheric oscillation experiments

We argue that regardless of the outcome of future Long Baseline experiments, additional information will be needed to unambiguously decide among the different scenarios of neutrino mixing. We use, for this purpose, a simple test of underground data: an asymmetry between downward and upward going events. Such an asymmetry, in which matter effects can be crucial, tests electron and muon neutrino data separately and can be compared with the theoretical prediction without relying on any simulation program.Comment: 9 pages, 2 figures (eps

Migration and Settlement: 11. Poland

As part of the comparative quantitative assessment of recent migration patterns and spatial population dynamics of IIASA's 17 National Member Organization countries, this report analyzes the changing population patterns in Poland and their relations to spatial policy. The analysis focuses on regional interdependence and the role of major urban agglomerations in Poland's spatial population system

Geophysical aspects of very long baseline neutrino experiments

Several proposed experiments will send beams of neutrinos through the Earth along paths with a source-receiver distance of hundreds or thousands of kilometers. Knowledge of the physical properties of the medium traversed by these beams, in particular the density, will be necessary in order to properly interpret the experimental data. Present geophysical knowledge allows the average density along a path with a length of several thousand km to be estimated with an accuracy of about $\pm 5$ per cent. Physicists planning neutrino beam experiments should decide whether or not this level of uncertainty is acceptable. If greater accuracy is required, intensive geophysical research on the Earth structure along the beam path should be conducted as part of the preparatory work on the experiments.Comment: 8 pages, uses elsart.cls. Talk given at 3rd International Workshop on Neutrino Factory based on Muon Storage Rings (NuFACT'01), Tsukuba, Japan, 24-30 May 200

A new method for determining the long‐period component of the source time function of large earthquakes

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94826/1/grl4270.pd

Neutrino parameters from matter effects in PeeP_{ee} at long baselines

We show that the earth matter effects in the ${\rm {\nu_e \to \nu_e}}$ survival probability can be used to cleanly determine the third leptonic mixing angle $\theta_{13}$ and the sign of the atmospheric neutrino mass squared difference, $\Delta m^2_{31}$, using a $\beta$-beam as a $\nu_e$ source.Comment: 4 pages, 4 eps figures; comments and references added, to appear in Phys. Rev.

Core-mantle boundary deformations and J2 variations resulting from the 2004 Sumatra earthquake

The deformation at the core-mantle boundary produced by the 2004 Sumatra earthquake is investigated by means of a semi-analytic theoretical model of global coseismic and postseismic deformation, predicting a millimetric coseismic perturbation over a large portion of the core-mantle boundary. Spectral features of such deformations are analysed and discussed. The time-dependent postseismic evolution of the elliptical part of the gravity field (J2) is also computed for different asthenosphere viscosity models. Our results show that, for asthenospheric viscosities smaller than 10^18 Pa s, the postseismic J2 variation in the next years is expected to leave a detectable signal in geodetic observations.Comment: 14 pages, 8 figures, 1 table. It will appear in Geophysical Journal Internationa

The Earth’s Interior: A New Frontier and a New Challenge for Earth Scientists

In this era of space exploration, deep expeditions to the ocean bottom and far viewing telescopes, the Earth's interior has emerged as one of the most challenging frontier areas for scientific investigation. Exploration of the crust, by seismic and other means, is well underway but our view of the underlying mantle and core is fuzzy. Plate tectonic theory has revolutionized Earth Science but we still do not understand the driving mechanism or why global processes change with time. The origins of the magnetic field, volcanism, earthquakes, mineral resources and mountain building processes are related to processes in the deep interior. Planetary exploration has opened up the new science of comparative planetology and yet, the most fundamental questions regarding the origin, evolution and composition of the Earth are unresolved because of our ignorance of the characteristics of most of our planet, the interior. The time is now ripe to make an integrated study of the Earth as a Planet or, in space age jargon, to undertake a mission to Planet Earth. There are several recent developments which make this timely

Report of the panel on earth structure and dynamics, section 6

The panel identified problems related to the dynamics of the core and mantle that should be addressed by NASA programs. They include investigating the geodynamo based on observations of the Earth's magnetic field, determining the rheology of the mantle from geodetic observations of post-glacial vertical motions and changes in the gravity field, and determining the coupling between plate motions and mantle flow from geodetic observations of plate deformation. Also emphasized is the importance of support for interdisciplinary research to combine various data sets with models which couple rheology, structure and dynamics