Abstract: This paper collects and analyzes the macroscopic anomalies before and after the May 12, 2008 Wenchuan M8.0 earthquake, Sichuan Province. The credible anomalies occurred from February 1 to June 10, 2008 were treated as macroscopic anomalies, then, space-time distribution of the macroscopic anomalies were studied. The results indicate that, in time distribution, the number of macroscopic anomalies reached peak value before the earthquake, and two peak values appeared after the earthquake. In space, the distribution of macroscopic anomalies before the earthquake was the same as after the earthquake. The reason why macroscopic anomalies occurred, the role of macroscopic anomalies in earthquake forecast were also discussed .

Key words: Wenchuan Earthquake, Macroscopic anomaly, Statistical analysis, Space-time distribution