Dr David Rothery, Dept of Earth & Environmental Sciences, the Open University, said:

"This morning's fatal magnitude 6.9 earthquake in China's Qinghai province was similar in magnitude and style to the quake that hit Haiti in January. Like the Haiti quake, it happened when the ground either side of a fault slipped sideways. In this case it was a consequence of India's northward collision into Asia, which for millions of years has slowly been forcing the Tibetan plateau out towards the east. The Qinghai quake happened at a depth of 10 km, slightly more shallow than the Haiti quake. When quakes are shallow, the shaking of the ground is more.
Earthquakes are common in this region, but there has not been anything so big within 200 km of the current epicentre since at least 1900.

"As usual in earthquakes, people have died because of the collapse of cheaply constructed buildings, in a poor region where it seems little regard has been paid to building codes that could have offered better protection to the people inside."