An earthquake with a magnitude of 7.3 jolted China's northwestern Qinghai province early Saturday, the US Geological Survey said -- following another tremor in the country's southwest that left at least two dead. The epicentre of the quake in Qinghai, which struck at 2:04 am (1804 GMT Friday) at a relatively shallow depth of 10 kilometres (six miles), was located about 400 kilometres southwest of the city of Xining, US seismologists said. The quake was initially measured at a magnitude of 7.4 but then slightly revised downwards by the USGS. The sparsely populated province is spread across the Tibetan plateau. In 2010, a 6.9-magnitude quake in Qinghai left 3,000 people dead or missing. bur-sst/ft