Che said that the office had not received any public report predicting the Wenchuan earthquake or accounts of abnormal animal behavior prior to the quake in the area. But media reports have said that toad swarms were seen in the streets in the region not long before the disaster. The CEA M&P division was responsible for managing such information. "If reports reached us, they would be properly processed," Che said.

With the internet, it is easy to find reports and videos of animal behavior anomalies and inexplicable natural phenomena, such as the sudden drainage of a water body, before an earthquake. Such phenomena might have a connection with a quake, but they also might not, an expert told Xinhua. These events could also be caused by climate change or a natural process that humans do not yet understand. CEA received such reports almost every day from around the country, one agency source said.

In retrospect, one can say that these were signs of an impending quake. But hindsight is often 20/20, one expert noted.

Forecast errors have consequences

Short-term forecasts should help people take precautions against an earthquake. But living in a tent or in the open air, especially if the weather was bad, could cause serious health problems and even deaths, especially if the forecast was not specific and the efforts dragged on for weeks or months. The direct and indirect costs might be huge, perhaps even comparable to the damage caused by a quake that hit unprepared people, the same expert said.

A successful forecast would justify the cost of preparation, however high, but a false alarm would make experts into scapegoats. So scientists were cautious.

Entrusted with the task of prediction, CEA experts had frequently found themselves asking what they should do.

The recent prediction of possible strong aftershocks in May 19-20 in the Wenchuan and neighboring areas was just such a trying moment. "We hesitated for hours," recalled a CEA senior researcher who was involved in the decision-making. The forecast was finally made out of a keen desire by the experts, perhaps also to redeem their prior failure.

The forecast turned out to be a for-nothing. But the public understood, and it exacted little extra cost on the affected communities, which were already on alert for any trembling underfoot.

Evidence, reasoning are key

Earthquake scientists anchor their studies on scientific evidence and reasoning. They would propose issuing an official forecast only when they believed the evidence supported doing so. This would be their defense and philosophy. Blame was part of life in the profession, one observer said.

Ill-supported predictions were like gambling. They were usually based on inadequate evidence or mere intuition. It would be luck if a prediction like that proved correct. But a real scientist would not do that, the same observer said.

"If quake scientists have done their job in accordance with the norm, they should not be blamed, whether for false alarms or zero alarms," said Zhang Dan, a veteran media consultant in Beijing.

In the Wenchuan case, the absence of an alarm was not dereliction of duty, at least not judging by the CEA experts' accounts.

Nonetheless, seismologists might feel even deeper sorrow than others, perhaps wishing that their forecasting ability was more advanced.

"I couldn't hold back tears in the office," said a scientist who asked not to be identified. "At the sight of the appalling scenes, especially the suffering of children, who wouldn't be disturbed?"

(Xinhua News Agency June 5, 2008)