中文摘要：

采用国家地震台网数十台地震仪的观测资料研究了汶川大地震和昆仑山大地震的“震前扰动”现象，结果表明，“震前扰动”现象与强台风的影响密切相关，适用于英国海洋学家Higgins的海浪非线性干涉理论中的“第二类脉动”．然而，通过对信号时频特征的细致分析后发现：“震前扰动”信号存在着明显的“时频偏移”现象，不完全符合“第二类脉动”的特征．因此本文认为，汶川大地震的“震前扰动”除了包含“第二类脉动”信号外，还可能存在着“第三类脉动”，这对强震短临前兆的研究有重要意义．

英文摘要：

We studied anomalous tremor before the 2008 great Wenchuan earthquake and the 2001 great Kunlunshan by analyzing seismic data from stations of National Digital Seismograph Network of China. Our results show that some anomalous tremor microseismic activities are related to West Pacific Typhoons, which are the secondary microseisms that are due to the non-linear interaction of ocean waves as proposed by Longuet-Higgins. However, we found that there are time-frequency shift between microseismic signals at different site after further investigation. This anomalous feature should not belong to secondary mieroseismie activity. We suggest that third mieroseisms are likely induced during process of the secondary microseisms propagation.