PERIODICITY OF GROUND FISSURES AND EARTHQUAKES IN THE EARTHQUAKE BELT OF THE WEIHE RIVER

In recent years, ground fissures were found in ten prefectures or cities in the earthquake belt of Weihe River. There are 7 ground fissures in Xian city that total 26.3 km in length. They constitute a great threat to city construction. The auther has also found historical fissures of the Han, Tang and Ming Dynasties buried ibelow the ground surface in the cities of Xianyang, Xian and Woman. These newly discovered fissures, together with 18 fissures recorded in history, form four groups each with a period of 700-800 years that conform with earthquake periodicity.The result of the observations may provide a new -basis, for the prediction of ground fissures and earthquakes in the earthquake belt of the Weihe River.