In the city of Mianzhu, 60 miles from the epicentre, bloggers pointed to reports just weeks before the earthquake of a mass migration of more than one million butterflies.

Other bloggers seized upon an as yet unsubstantiated rumour that a Chinese geologist had predicted the earthquake in advance but had been stifled by the authorities, and by fear.

"On the seventh of May, a geologist predicted this [earthquake]," wrote one blogger. "But he didn't dare make it public."

Another blogger from Beijing wrote: “Everyone is talking about the rescue effort but they are not actually joining it.

“So, instead we should turn our thoughts to why [the authorities] didn’t forecast the earthquake and evacuate the people...

“Could it be that it was out of a desire for a peaceful Olympics?”