Abstract:We chose the continuous waveform data of 40 days from 169 seismograph stations within 800 km from the epicenter of the Wenchuan earthquake as the research object and analyze the probable abnormal signals. Two kinds of obvious and ubiquitous abnormal signals are found: (1) spindle anomalies, which are found in ~63% of stations, with duration of 1.5 days to 2 days, absolute values of the amplitudes around ~1 700 count and dominant frequency of 0.2~0.3 Hz, and (2) jump anomalies, which are observed in ~15% of stations, with more in north-south component, duration around 2 000 s, amplitudes of ~2 000 count and dominant frequency of 0.1~0.2 Hz. It is indicated that the formation of spindle anomaly is more likely due to the influence of typhoon, and that the jump anomaly may be have the mechanism of the new precursor theory of solitary wave. The results are helpful in understanding the seismogenic process and capturing earthquake precursors.