The images showed Beichuan, one of the worst-hit areas in Sichuan province, in May 2006 and after Monday’s disaster on Wednesday. The pictures revealed a large forest, school and clusters of residential houses along a river had been wiped out by the quake, and a road along the river was severely damaged.

“The images, which are free of charge, are expected to be used as references in China’s efforts searching and rescuing the people still missing in Sichuan,” Harry Chang, a professor of National Taiwan Normal University, told AFP.

Change said the images were collected by the FORMOSAT-2 satellite, a science research craft owned by Taiwan, and given to the Chinese Academy of Sciences.

Chang estimated that in Beichuan, the tremor also had caused landslides covering some 1,500 hectares (3,705 acres), which had blocked the river.

“Accordingly, several new lakes have been formed. What is dangerous is that should the new lakes burst, the residents living in the low-lying areas of the river would be in danger,” he said.

Chang also warned of mudslides caused by rain, saying “it would make the rescue work more difficult.”