Aftershocks threaten swollen China 'quake lake'

CHENGDU, China (AFP) — Aftershocks Monday continued to threaten the stability of a swollen "quake lake" in southwest China, amid urgent efforts to drain its rising waters to prevent a flood downstream.

A 5.0-magnitude aftershock rattled the area of quake-devastated Sichuan province where the lake is located on Monday, US seismologists reported. An aftershock of the same strength struck the region on Sunday.

A local official in the city of Mianyang, located not far from the Tangjiashan lake, said the aftershocks had so far not had any impact on the unstable body of water.

But Xinhua said Sunday's tremor had caused "massive landslides" on nearby mountains, and state television said Monday that the situation remained "highly dangerous," with hundreds of thousands of people living downstream.

The lake has become one of the most pressing issues in the aftermath of the May 12 quake that struck mountainous Sichuan, killing 69,142 and leaving 17,551 others missing, according to the latest toll issued Monday.

Millions more have been left homeless by the 8.0-magnitude quake, which triggered huge landslides that blocked rivers and created more than 30 unstable "quake lakes," including the Tangjiashan one on the Jianjiang river.

Soldiers were rushing Monday to clear a third channel to drain water from the lake, the state-run China Daily reported, in a race against time to reduce the risk that it might burst its banks.

Troops began draining water through one hastily dug channel on Saturday to stop the lake from emptying all at once.

The water resources ministry said Monday the water level had risen by nearly one metre (three feet) in a 24-hour period -- double the rate of the water flowing out through the drainage channels.

About 6,900 cubic metres of water -- the equivalent of nearly three Olympic-sized swimming pools -- were flowing into the lake every minute, the ministry said.

Troops working at the lake triggered 10 explosions on Monday to accelerate drainage, but only 3,000 cubic metres of water were now flowing out every minute, Xinhua reported.

Torrential rain was forecast for much of southern China over the next few days, but was not expected to affect quake-hit areas of Sichuan, the country's meteorological centre said.

The quake zone was however due to see searing hot temperatures -- an unwelcome piece of news for the millions of displaced people living in tents.

Heatstroke and related ailments are bringing increasing numbers of people from the makeshift refugee camps to a field hospital in quake-ravaged Dujiangyan.

"This could be a very big problem as the weather gets hotter," said Zou Hejian, who heads up the medical staff at the temporary facility.