汶川地震前地震连续波形资料中的异常信号

以汶川地震震中距800 km范围内169个地震台站在震前40 d的连续波形资料为研究对象，分析其记录的可能异常信号，得到了两类比较明显、影响范围较大的震前异常信号，按照信号波形形态称之为：1）纺锤状异常。在约63%的台站中出现，持续时间1.5~2 d，振幅绝对值大多为1 700 count，优势频率约为0.2 ~0.3 Hz。 2）突跳异常。在约15%的台站出现，在南北分量出现较多，持续时间大多在2 000 s左右，振幅大多±2 000 count，优势频率约为0.1 ~0.2 Hz。分析异常机制认为，纺锤状异常可能与台风影响有关，突跳异常可能符合较新的孤立波前兆解释。该研究结果有助于深入了解地震孕震过程和地震前兆异常信号的捕捉。

The Abnormal Signals in Continuous Waveform Data before Wenchuan Earthquake

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.