A strong earthquake toppled homes and schools in the remote mountainous Tibetan Plateau of southwest China on April 14, 2010, killing hundreds of people.
More than 10,000 people were injured and thousands left homeless in freezing conditions after a series of quakes and aftershocks caused many low, mud-brick buildings to collapse, residents and state media said.
Troops and aid shipments were dispatched to Qinghai Province's Yushu county, although rescue and relief efforts were likely to be hampered by damaged roads and bridges.
The main 6.9-magnitude quake was centred in the mountains that divide Qinghai province from the Tibet Autonomous Region, 150 miles (240 km) north northwest of Qamdo in Tibet and 235 miles (375 km) south southeast of the mining town of Golmud in Qinghai, the United States Geological Service said. It had a depth of 6.2 miles (10 km).
State media reported that the early morning quake caused some schools and part of a government office building to cave in. Some students were trapped in the rubble, it said, although residents said most had been able to flee to playgrounds.
After the devastating May 2008 earthquake in Sichuan Province, which killed 80,000, the widespread collapse of school buildings caused anger and accusations of corruption.
The Tibetan plateau is regularly shaken by earthquakes, though casualties are usually minimal because so few people live there.
Yushu is home to some 100,000 people, spread over a vast area, but the quake struck near the relatively highly-populated county seat of Jyeku.
The foothills to the south and east of the area are home to herders and the Tibetan monasteries of Yushu county, while the area to the north and west is arid and desolate.