Solid Earth Physics – University of Copenhagen

The three disciplines in Solid Earth Physics:

Research in the physics of the solid Earth is based on three different disciplines: Field experiments, theory and numerical modelling. The measurements draw on data derived from registration of seismic waves, produced by explosions or remote earthquakes, and satellite measurements of the Earth´s gravity and magnetic fields. Theoretical and numerical investigation is comprised of analysis and simulations of currents in the outer core of the Earth and development of methods applied in the calculation of the structure of the Earth. These methods are based on simulations of seismic and electromagnetic waves in the Earth and play an important part in the search for oil, gas and potable water in the underground.

Of particular interest to the Solid Earth Geophysicists is presently:

The heat currents of the Earth, mapped out using the magnetic field. Irregularities in the heat current through the surface of the Earth are very difficult to measure in ice covered areas of the Earth. An analysis of magnetic data, gathered by satellites over Antarctica, has revealed volcanic areas, as well as uncovered the causes of the so called “ice currents”, - ice flowing abnormally fast.

The Inner structure of the moon.
Daily laser distance measurements between the Earth and the Moon allow for the determination of the stiffness of the moon´s crust and the deformation caused by the attraction of the Sun and Earth. Subsequently for a calculation of the elastic characteristics of the inner structure of the moon as well. Our results indicate that a small part of the Moon´s core is liquid and has a radius of a few hundred kilometers. The composition of minerals in the inside of the Moon have been calculated from seismic data as well as from variations in the electromagnetic field around the Moon. These new results shed new light on the prevalent theory that the Moon is the result of a collision between the Earth and a planet the size of Mars.

Seismic Anisotropy.
Deformation and flow in the lithosphere and asthenosphere of the Earth can be studied by mapping the directional dependency of seismic wave propagation velocities. The underground in East Greenland has been investigated analyzing waves from distant earthquakes, and the results support the theory that the hot, uprising magma current that is presently under the volcanoes of Iceland, were under Greenland app. 60 million years ago.

Inverse Theory and Geostatistics.
The combination of inverse theory and geostatistical theory has made the solution of geophysical, inverse problems of so far unequalled complexity possible. A good example of this, is the fact that solutions to a tomographical problem with a predefined pattern, can be computed very efficiently. The method has obvious application opportunities in connection with hydro and oil geological problems.