The biggest crash on Earth: India slides under Tibet, but how?

The clash of the two continents is very complex. The Indian plate, for example, is compressed where it collides with the very rigid plate of the Tarim Basin at the northwestern edge of Tibet. On the eastern edge of Tibet, the Wenchuan earthquake in May 2008 claimed over 70,000 lives.

Scientists at the GFZ German Research Center for Geosciences report in the latest issue of the journal Science on the results of a new seismic method which was used to investigate the collision process.

In international cooperation, it was possible to follow the route of the approximately 100-kilometer-thick Indian continental plate beneath Tibet. To achieve this, a series of large seismic experiments was carried out in Tibet, during which the naturally occurring earthquakes were recorded. By evaluating weak waves that were scattered at the lower edge of the continental plate, this edge was made visible in detail. The boundary between the rigid lithosphere and the softer asthenosphere proved to be much more pronounced than was previously believed.

The entire Indian sub-continent moves continuously north over millions of years and has moved 2 meters below Tibet in the last 50 years alone. The Himalayas and the highlands of Tibet, the highest and largest plateau in the world, were formed this way. But the recurring catastrophic earthquakes in China are also caused by this collision of two continents.

Researchers hope this latest work will provide a better understanding of the processes involved in the collision of the two plates, and ultimately reduce the earthquake risk to millions of people across the entire collision zone.