The 7.8 quake that shook China is a shift of the Tibetan plateau [wiki].
India crashes into Tibet, China is drawn under. The Indian plate moves north at speeds of around 150mm per year—much faster than any plate. [link] Because India is hitting head-on, the Tibetan plateau is developing splits, or rifts, that curve away from the axis of impact. The Indian subcontinent is sliding under Tibet and lifting the plateau, already the highest region on earth. [link]
Different parts of the Tibetan plateau were elevated at different times. Interestingly, the great Himalaya mountains uplifted significantly later and were below sea level at a time when the central plateau was already more than 4,500 meters (14,850 feet). [link]
This quake struck from a depth of ten kilometres, says USGS. [story]
It’s silly to project trends, but few westerners know there have been several forceful earthquakes in Asia recently. “A 7.3 magnitude earthquake occurred in Japan not long ago. On the Chinese mainland, a 6.9 magnitude quake took place in Tibet in January, while March saw a 7.3 magnitude quake in Xinjiang and now a 7.8 magnitude quake in Wenchuan.” [link]
An astronaut’s pic of the Tibetan Plateau here.
To remind us that San Francisco survives atop tectonic fractures, here’s a very impressive astronaut’s pic of California’s fault at Point Reyes.
The distinct blue line is the Tomales Bay over the rigorous San Andreas fault. The entire peninsula was once shifted 30 miles northward during one series of quakes – and may be remnant of lands near Australia as it’s circled the Pacific’s Ring of Fire.