【摘要】 文章以渤海地区为例，基于对渤海强阵风时段33个宽频带地震台站观测数据的时频谱分析，研究了第二类地脉动特征及其对地震背景噪声的影响，并对第二类地脉动激发机制提出了新的观点。研究表明，短周期倍频（short-period double-frequency,SPDF）地脉动和长周期倍频（long-period double-frequency,LPDF）地脉动在渤海西北部地区呈现较明显的交替增强和减弱过程。SPDF地脉动是近岸强海风时段由无规则风浪激发，频带较宽，分布在0.2–1Hz范围内；LPDF地脉动是海风减弱时段，由较规整的涌浪激发，频带较窄，主要集中在0.15–0.3Hz之间。从时间维度上，随着海风减弱，SPDF地脉动能量减弱，主频升高，LPDF地脉动能量增强，主频降低，与风浪的消衰和涌浪的成长过程一致；从空间维度上，随着脉动向内陆传播，SPDF地脉动优势频段下降和能量衰减明显，LPDF地脉动未发生明显变化，且当地脉动能量较强时，在沿高海拔地区传播过程中，会呈现一定的场地放大效应。研究结果对第二类地脉动基础理论进行了重要的补充，初步揭示了大气、海洋与地震背景噪声之间的关系，为基于第二类地脉动特征开展地学和海洋学相关研究，提供了重要的理论参考。更多还原

【Abstract】 In this study, we use the Bohai Sea area as an example to investigate the characteristics of secondary microseisms and their impact on seismic noise based on the temporal frequency spectral analysis of observation data from 33 broadband seismic stations during strong gust periods, and new perspectives are proposed on the generation mechanisms of secondary microseisms. The results show that short-period doublefrequency(SPDF) and long-period double-frequency(LPDF) microseisms exhibit significant alternating trends of strengthening and weakening in the northwest area of the Bohai Sea. SPDF microseisms are generated by irregular wind waves during strong of fshore wind periods, with a broad frequency band distributed in the range of 0.2–1 Hz; LPDF microseisms are generated by regular swells during periods of sea wind weakening, with a narrow frequency band concentrated between 0.15 and 0.3 Hz. In terms of temporal dimensions, as the sea wind weakens, the energy of SPDF microseisms weakens, and the dominant frequencies increase, whereas the energy of LPDF microseisms strengthens and the dominant frequencies decrease, which is consistent with the process of the decay of wind waves and the growth of swells. In terms of spatial dimensions, as the microseisms propagate inland areas, the advantageous frequency band and energy of SPDF microseisms are reduced and significantly attenuated, respectively, whereas LPDF microseisms show no significant changes. And during the propagation process in high-elevation areas, LPDF microseisms exhibit a certain site amplification ef fect when the energy is strong. The results provide important supplements to the basic theory of secondary microseisms, preliminarily reveal the relationship between the atmosphere, ocean, and seismic noise, and provide important theoretical references for conducting geological and oceanographic research based on the characteristics of secondary microseisms.更多还原