Internal geophysics at the Belgian research institutions

What is 'internal geophysics' and how is it related to exploration geophysics? To be a geophysicist means to study the earth with physical methods. We speak of 'internal geophysics' if we mean by 'the earth' its solid part. Understood in this way, internal geophysics includes exploration geophysics. The 'internal geophysicist' is motivated primarily by the desire to understand what goes on inside the earth, while the exploration geophysicist is motivated primarily by the economic necessity to find oil, minerals, or water. The different motivation leads us on different paths, but the common foundations of our work means that there are a number of similarities and sometimes surprising cross-connections. For more than a century research in internal geophysics has been conducted at three Belgian national scientific institutions: the Royal Observatory, the Royal Meteorological Institute and the National Geographical Institute. Fields of particular interest are: precise positioning, gravimetry, earth tides, seismology, magnetism and palaeomagnetism.