The views on abnormal celestial phenomena in ancient China originated from human intuitive vigilance and fear of abnormal things; Under the idea that the heaven was related to human beings; the concept of abnormal celestial phenomena did not vdnish with the developmeat of astronomy.

The reasons of food crisis included many aspects: frequent occurrence of natural disasters, backwardness of production technology, feudal exploitation, warlords rule, bandits looter, for.

During the period the frequent visits of wars and natural disasters bring the area intensive impacts upon its social ecology in a whole,and as a result dramastic changes,negative or positive,take place in economy,politics and social humanist environment.

Natural disasters along the Qinghai-Xizang railway and their prediction;