Abstract: M_S5.9 earthquake occurred in Balinzuoqi and Alukeerqinqi region on August 16, 2003. This earthquake occurred at edge of 2003 year seismically risk zone. In this paper, on the basis of main evidence of the year risk zone and anomaly tracking, the authors analyzed the precursory anomalies including groundwater level of Dadianzi well and Kulun; water radon of Kailu well before M_S5.9 earthquake. At the same time, the authors also analyzed and studied the precursory anomalies around Inner Mongolia region. The result shows that there is a group of trend anomalies and medium-short term anomalies before this earthquake.

Key words: M_S5.9 earthquake, Precursory anomalies, Macroscopic anomalies, Ground fluid