Almost as soon as the initial aftershocks stopped reverberating last week, the rumors began. Some say that frogs, insects and other animals fled shortly before the earth shook. Others insist that water mysteriously drained from ponds, or that Beijing knew the massive earthquake would strike but chose not to publicize it with the Olympics around the corner.
Patently false, perhaps, but enough to alarm the Chinese leadership.
"Stop rumors to avoid social panic and stabilize order," said an earthquake report issued Wednesday by the government of hard-hit Mianyang. On the same day, Beijing announced that it had punished four people in northern China for spreading rumors on the Internet about the quake, without explaining what the punishment was.
Rumors are an integral part of Chinese folk history, songs and poetry. Last year, authorities drained a reservoir in central Sichuan province to dispel rumors that a growling water beast lived there. In 2006 a rumor spread in Anhui province that the virus that causes AIDS was being injected into watermelons, devastating sales.
Chinese emperors long sought to halt the spread across their far-flung empire, with the first recorded anti-hearsay campaign launched by King Li nearly 3,000 years ago, despite a proverb: "Trying to stop people's mouths is like trying to stop a flood."
More enlightened rulers sent envoys out to collect rumors as barometers of underlying concerns. But many others, particularly toward the end of dynasties, initiated crackdowns during famines, floods and unrest.
The recent crackdown on rumors involving the earthquake follows a similar campaign launched in late April in the wake of the Tibet uprising, efforts some say amount to trying to stamp out one of the most powerful communication forms in human history.
Governments everywhere work hard to control the message. But this is especially important for a one-party state with limited democracy and a restive population, and fearful that instability could undermine its legitimacy.
Since riots broke out in mid-March in the ethnic Tibetan areas, China has offered a single narrative: that the violence was sparked by a few extremists directed by the Dalai Lama, the exiled Tibetan spiritual leader; that Tibet has always been part of China; and that the government has brought enormous economic benefit to a backward population.
With its grip secure on newspapers, television and the Internet, hearsay represents a major threat to the government's control.
"If people start doubting the official line on particular events, what's to stop them from doubting all sorts of things?" said Joshua Rosenzweig with the San Francisco-based Dui Hua Foundation, a human rights group. "That's something the party wants to avoid."
Particularly worrisome for Beijing is information from the self-proclaimed Tibetan government in exile in northern India.
Rumor has particular currency in Tibet because illiteracy is high, some say, especially in rural areas. "It's just mouth to mouth," said Tseten Wangchuk with the Voice of America's Tibetan service. "There's an invisible bubble of language and trust. Once you're inside, you hear all sorts of things."
These range from the plausible to the bizarre, including one a few years ago that a frog the size of a truck had frustrated Chinese engineers trying to build the world's highest railway to Lhasa, Tibet's capital.
"In a way, it's laughable; in a way, it's sad," Wangchuk said. "It's a means of expressing psychological resentment, [to] get out feelings, in this case that you hate the railway."
Spreading rumors is a crime under anti-subversion sections of China's 1993 State Security Law and lesser provisions outlawing "anti-splittism" or "fabricating or deliberately disseminating false alarmist information."
Arrests on rumor charges followed the 1989 student crackdown in Beijing's Tiananmen Square and the SARS outbreak in 2003. In April, human rights activist Hu Jia was sentenced to 3 1/2 years after a court found that he "spread malicious rumors and committed libel," and this month a man in the eastern province of Jiangsu was jailed for claiming online that he planned to grab the Olympic torch during its relay, which drew protests around the world.
A major fear for Beijing is that rumors can spark conflict. The initial, mild demonstrations March 10 at the Sera and Drepung monasteries in Lhasa may have been inspired by a rumor a few weeks earlier that Tibetan exiles marching in India on that day were to cross the border into China.
"Spreading rumors leads to bad results," said Lian Xiangmin, research director with the China Tibetology Research Center in Beijing. "Tibetans have developed very slowly, with rumor a major form of communication."
A major conduit for rumors are the many tent communities in post-quake Sichuan or the teahouses in Lhasa. In Tibet, however, many customers in recent weeks have shunned those establishments, fearing spies. Government intimidation also appears to be working elsewhere. Voice of America and exile groups say they're receiving fewer reports from Tibet.
"Rumor is now defined so broadly, it basically involves anything that isn't the party line," the VOA's Wangchuk said.
But their spread can also be patchy, selective and inaccurate.
"In our news-rich world, we're quite unable to imagine such uneven news flow," said Robbie Barnett, a professor at Columbia University. "We know something will be on the radio in an hour or two. They live in a shadow world."
Among the rumors periodically heard in Tibet are claims that Chinese or Muslim minority members known as Hui are trying to poison Tibetans through the water supply or soups. Others suggest that the Dalai Lama's image was seen in the moon, that he's returning from exile or that religious statues have stood up and walked after earthquakes. A rumor in mid-July 2006 that the Dalai Lama was due to return prompted thousands of Tibetans to walk for days to reach the Kumbum monastery in Qinghai province.
Historically, because rumors frequently were true, or at least were exciting to pass along, they have taken on the power of omens. Wannabe emperors sometimes fanned self-serving rumors that their name was discovered in the bowels of a fish or on a meteorite.
Chinese rulers fighting rumors have argued that educated, moral people don't stoop to such levels.
"The problem is that many rumors are started by educated people" with ulterior motives, said Lu Zongli, a professor at the Hong Kong University of Science and Technology.
"It's universal. It's just human nature."