Strong aftershock causes more misery in China

By Chris Buckley

BEICHUAN, China (Reuters) - A strong aftershock jolted southwest China on Sunday killing at least one person and injuring 400 others, state media said, nearly a fortnight after a big earthquake killed tens of thousands in the same area.

More than 70,000 houses were toppled during Sunday's tremor in Qingchuan, Sichuan province, state television reported. The 5.8 magnitude aftershock was epicentered 40 km (25 miles) west-northwest of Guangyuan, the U.S. Geological Survey said.

A local official in Guangyuan county said one person was killed and 24 hurt in collapsed houses or landslides, Xinhua state news agency reported.

Almost all of Qingchuan's houses had been declared unsafe after a devastating earthquake on May 12, and residents had moved into tents on the fringes of town. A mountain slope abutting the town had shown a crack, leading to fears it could smother part of the city in a landslide.

One of Sichuan's worrisome "quake lakes", formed when landslides block a river, is also near the aftershock's epicenter in Hongguang.

As the aftershock occurred, hundreds of troops carrying explosives were trekking to reach another, even larger quake lake that threatened a secondary disaster.

Concerned by a steep rise in the water level of a giant lake at Tangjiashan on the Jian River, authorities want to blast a hole in the barrier before it bursts and causes a flash flood. Thousands below the lake have been evacuated as a precaution.

"I can assure the people who need to be moved have already been safely relocated," said a general, who gave his name only as Zhou, watching over hundreds of troops outside the wrecked town of Beichuan as they readied to march to the lake.

Premier Wen Jiabao, who believes the overall death toll from the May 12 quake could exceed 80,000, has said the main concerns are secondary disasters like flooding and landslides, epidemics, and providing shelter for the 5 million displaced.

Hundreds of aftershocks have rattled the area since the 7.9 magnitude quake.

State television earlier reported that an 80-year-old partially paralyzed man was pulled alive from the rubble on Friday, 266 hours after the main quake hit.

The man was rescued in Mianzhu city, where he had been trapped under a collapsed pillar of his house. He had survived after being fed by his wife, the television report said.

PRECAUTIONARY STEP

In the last century about 5,500 people were killed by flash floods after barrier lakes burst through dams made by landslides, according to a 2004 paper by geologists at the Chinese Academy of Sciences. In 1786, the breach of a landslide dam 10 days after a major earthquake killed about 100,000 people in Sichuan province.

The mountainous region along the faultline is densely packed dams, raising concerns that if either the quake lakes or the weakened dams burst, the rush of water could cause other dams to fail.