Hundreds of troops carrying explosives trekked through a quake-devastated area in southwest China on Sunday, attempting to reach a "quake lake" that threatens a secondary disaster. Concerned by a steep rise in the water level of a giant lake at Tangjiashan, authorities want to blast a hole in the barrier before it bursts and causes a flashflood. Thousands have been evacuated below the lake as a precaution. Also on Sunday, state television reported an 80-year-old partially paralysed man had been pulled alive from rubble, 266 hours after the 7.9 magnitude quake hit.