Sources of primary and secondary microseisms
Sources of primary and secondary microseisms
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DOI：
10.1785/bssa0840010142
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发表时间：
1994-02
影响因子：
3
通讯作者：
R. Cessaro
中科院分区：
文献类型：
--
作者：
R. Cessaro
低频（0.01至0.2赫兹）地震噪音，由远洋风暴产生，通常被观测为来自陆地和海底探测器的地震记录中的微震。在微震研究中，一个主要的研究目标是确定其震源。本文报告了一次和二次微震的分析（即，在20世纪70年代早期，在三个陆基长周期阵列（阿拉斯加长周期阵列、蒙大拿大孔径地震阵列和挪威地震阵列）上同时记录的地震波（接近海洋涌浪的频率，频率是海洋涌浪的两倍）。可靠的微震源位置确定的广角三角测量，使用的方位角的方法获得的频率波数分析的记录传播通过这些阵列的微震。一次和二次微震的两个近岸源似乎是持久的，在这个意义上说，它们与基本上恒定的近岸位置。观测到的次级微震，除了为初级微震确定的相同近岸位置外，还来自广泛的远洋位置。
Low-frequency (0.01 to 0.2 Hz) seismic noise, arising from pelagic storms, is commonly observed as microseisms in seismic records from land and ocean bottom detectors. One principal research objective, in the study of microseisms, has been to locate their sources. This article reports on an analysis of primary and secondary microseisms (i.e., near and double the frequency of ocean swell) recorded simultaneously on three land-based long-period arrays (Alaskan Long Period Array, Montana Large Aperture Seismic Array, and Norwegian Seismic Array) during the early 1970s. Reliable microseism source locations are determined by wide-angle triangulation, using the azimuths of approach obtained from frequency-wave number analysis of the records of microseisms propagating across these arrays. Two near-shore sources of both primary and secondary microseisms appear to be persistent in the sense that they are associated with essentially constant near-shore locations. Secondary microseisms are observed to emanate from wide-ranging pelagic locations in addition to the same near-shore locations determined for the primary microseisms.