As Alfred Wegener already recognized 100 years ago, the giant southern continent, Gondwanaland, broke about 200 million years ago into several pieces which drifted apart. One part, India, drifted northward until it collided 50 million years ago with Eurasia.
This collision created the Himalayan mountain chain and the Tibetan plateau, which are not only very significant geological structures, but are also important parts of the Earth System. The influence of Tibet on the atmospheric circulation and world climate and the ongoing threat of giant collisional earthquakes to the megacities in the Ganges plain must be emphasized. In international cooperation, the GFZ conducted a number of seismic experiments in Tibet, known as INDEPTH experiments, to study details of the deformation of the tectonic plates as a consequence of the collision. As a result the presence of the Indian lithosphere was for the first time seismologically demonstrated to exist several hundred kilometers northwards below Tibet. During the collision the Indian crust was peeled off and contributes to the thickening of the Tibetan crust. The latest phase of the INDEPTH experiments was focused on the northern margin. Using active and passive seismic techniques (wide-angle profiling, receiver functions, surface wave tomography), we have imaged the deep structure below Tibet, showing the configuration of the Tibetan lithosphere between the Indian and Eurasian plates. We also found evidence for unusual properties of the lower crust, which are likely to be responsible for the prevalence of crustal flow in northern Tibet.