Section 2.5: Geodynamic Modeling

The dynamic processes within the Earth are not only hidden from direct observation because they take place at unreachable depths. They also occur on time scales that are much slower than humans can sense. While the ruptures in earthquakes race at speeds of about 10,000 kilometers per hour through fault zones, the huge lithospheric plates shift at paces slower than a fingernail grows. Earth scientists must thus be able to handle fractions of a second as easily as time spans of millions of years.

In our Section, we have developed numerical methods which can simulate the details of dynamical processes which take place on such dissimilar time scales. We use them, for example, to simulate the rupture processes in earthquakes. The calculated results serve, in part, as input for modelling tsunamis as part of the German Tsunami Early Warning System in Indonesia.

We are particularly interested, however, in simulating the deformation in the Earth's crust and mantle that occurs where lithospheric plates interact, as they do at transform faults or in subduction zones. These interactions generate heat, which not only affects the mechanical behaviour of rocks but can also produce petrological changes. Since we take the thermomechanical and petrophysical changes into account in our simulations, their output is especially realistic. They therefore also contribute as input to a new system for tsunami warnings, called GPS-Shield, based mainly on GPS measurements of crustal deformation. Since our modelling methods take many input parameters into account, they also support the unified analysis and interpretation of many different geophysical, geological and geochemical measurements.