Materials of the International Conference
50th Anniversary of the International Geophysical Year
and Electronic Geophysical Year

16-19 September 2007 • Suzdal, Russia

New information on the inner Earth from dedicated satellite missions

M. Diament

Institut de Physique du Globe de Paris, Paris, France

Abstract

In the last decades, a dramatic improvement of our knowledge of the structure of the inner Earth and processes acting there arose thanks to satellite missions. Nowadays, satellite geophysical data are an essential component of an observing and monitoring system of our planet. Geomagnetism greatly benefited from the combined acquisition of data in ground observatories and by several satellite missions (Champ, Orsted, Swarm...). Ice topography and its evolution, for example in polar areas can be monitored thanks to several existing and planned satellite altimetry missions. Measurements of the ground movements in tectonically active zones, on active volcanoes or in areas affected by movements due to human activities are easily performed thanks to time series based on very high resolution optical satellite imagery, satellite geodesy (GNSS) and satellite radar interferometry. As far as gravity is concerned, a global, high resolution, gravity field of the Earth had been recently obtained from satellites. Data of the European Space agency mission GOCE that will be shortly launched will even more improve the quality of this static field. This will allow to gain much insight in the knowledge of the deep Earth in many areas very poorly previously covered by ground data as was already shown for example in addressing the question of the origin of the volcanism in French Polynesia. New types of data became also available thanks to the GRACE mission. Data from this mission allowed to provide time series of the gravity field over the entire globe with an unprecedented accuracy and resolution. Numerous results on the monitoring and modeling of the gravity variations due to mass transfers within the geofluid envelops have been published as for example for the large scale water storages or for ice mass variations in Antarctica or Greenland. These data also reflect mass redistributions in the solid Earth as the ones associated with large earthquakes. It has been shown that the gravity signature of very large earthquakes could indeed be detected in satellite gravity data such as the GRACE mission or future, more-accurate ones. In particular, since they provide unique information for oceanic areas where little or no surface data are available they appear as a very promising tool for studying and perhaps monitoring of subduction zones where the largest, most devastating earthquakes, take place.

Citation: M. Diament (2007), New information on the inner Earth from dedicated satellite missions, in: Materials of the International Conference '50th Anniversary of the International Geophysical Year and Electronic Geophysical Year', GC RAS, Moscow, doi:10.2205/2007-IGY50conf.

© 2007 Geophysical Center RAS and authors


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