A senior official at China's Earthquake Administration has expressed his deep regret for not being able to predict the deadly earthquake in Sichuan last May.

Yin Chaomin is the deputy director of the administration.

"We were not able to forecast the 8-magnitude earthquake, because the geological structure in the quake zone is very complex. There was no evidence or signs of an earthquake before it took place. As a staff member in the field, I deeply regret it."

Yin Chaomin says although China's earthquake-monitoring system has the capacity to predict some earthquakes, knowledge of the earth's inner layer and earthquake activities is still quite limited.

He says issuing early warnings for earthquakes is a huge challenge worldwide and that failures to predict earthquakes have greatly outnumbered successes in the history of earthquake forecasting.