Five minutes after the magnitude-7 earthquake hit Ya'an, Sichuan province, at 8:02 am on Saturday morning, a micro-blogger posting under the name Ma Jun-John said that people at the airport in Chengdu, capital of Sichuan, panicked because the terminal had been shaking so violently.

"It felt like the terminal could collapse at any moment," he wrote on the popular Sina Weibo micro-blog platform, which has more than 400 million users, 60,000 of them government agencies.

At 8:12 am, China Earthquake Network Center confirmed the quake on its micro blog and within minutes, Sina Weibo was filled with information about the seismic activity and disaster relief.

Shan Xuegang, a researcher at the People's Daily website, said that when in 2008 the magnitude-8 quake struck Wenchuan, in Sichuan, micro blogs had not yet become popular, but now they serve as a key platform for people to interact.

"With these (micro blog) services, everyone is a reporter. They can tell what happened in disaster areas and what they urgently need, and this will improve the efficiency of rescue efforts," Shan said.

At 8:29 am, the China International Rescue Team urged people in areas hit by the quake to report their location and the damage via micro blog with cellphones if possible. More than 36,000 comments were left under that post, which had been forwarded more than 391,500 times by 5 pm on Saturday.

At 8:47 am, a micro-blogger from Lushan county, the hardest-hit area, said many houses had collapsed and there were casualties. He asked for help. He then posted a couple of photographs showing the damage. These were among the first group of photos from the disaster zone before traditional media arrived at the scene.

Yu Guoming, director of the Institute of Public Opinion at Renmin University of China in Beijing, spoke highly of the role of social media in the earthquake saying it is a great supplement to traditional media.

"Social media, such as micro blogs, can be faster and spread more information than television and newspapers," Yu said.

The official media and traditional channels should update this disaster information quickly to help ease the public's doubts and prevent online rumors, he said.

"But we cannot rely on social-networking media alone, which sometimes offer only patchy or exaggerated information. In other words, these sources lack authority to some extent," he said.

A series of photos of collapsed buildings purportedly in the quake zones that were posted on micro blogs Saturday morning were later proved to be a fraud.