Retrospection on the Conclusions of Earthquake Tendency Forecast before the Wenchuan Ms8.0 Earthquake

The reason for the failure to forecast the Wenchuan Ms8.0 earthquake is under study, based on the systematically collection of the seismicity anomalies and their analysis results from annual earthquake tendency forecasts between the 2001 Western Kuulun Mountains Pass Ms8.1 earthquake and the 2008 Wenchuan Ms8.0 earthquake. The results show that the earthquake tendency estimation of Chinese Mainland is for strong earthquakes to occur in the active stage, and that there is still potential for the occurrence of a Ms8.0 large earthquake in Chinese Mainland after the 2001 Western Kunlun Mountains Pass earthquake. However the phenomena that many large earthquakes occurred around Chinese Mainland, and the 6-year long quietude of Ms7.0 earthquake and an obvious quietude of Ms5.0 and Ms6.0 earthquakes during 2002 ～2007 led to the distinctly lower forecast estimation of earthquake tendency in Chinese Mainland after 2006. The middle part in the north-south seismic belt has been designated a seismic risk area of strong earthquake in recent years, but, the estimation of the risk degree in Southwestern China is insufficient after the Ning'er Ms6.4 earthquake in Yunnan in 2007. There are no records of earthquakes with Ms≥7.0 in the Longmenshan fault, which is one of reasons that this fault was not considered a seismic risk area of strong earthquakes in recent years.

作 者： Liu Jie Guo Tieshuan Yang Liming Su Youjin Li Gang   作者單位： Liu Jie,Guo Tieshuan,Li Gang(China Earthquake Networks Center, Beijing 100045, China)

Yang Liming(Earthquake Administration of Gansu Province, Lanzhou 730000, China)

Su Youjin(Earthquake Administration of Yunnaa Province, Kunming 650224, China) 

刊 名： 中國地震研究（英文版）  英文刊名： EARTHQUAKE RESEARCH IN CHINA  年，卷(期)： 2009 23(2)  分類號： P3  關鍵詞： Wenchuan earthquake   Annual earthquake tendency   Seismicity   Seismic risk area of strong earthquake