Passive seismic monitoring in the oceans uses long-term deployments of Ocean Bottom Seismometers (OBSs). An OBS usually records the three components of ground motion and pressure, typically at 100Hz. This makes the OBS an ideal tool to investigate fin and blue whales that vocalize at frequencies below 45Hz. Previous applications of OBS data to locate whale calls have relied on single channel analyses that disregard the information that is conveyed by the horizontal seismic channels. Recently, Harris, Matias, Thomas, Harwood, and Geissler [J. Acoust. Soc. Am. 134, 3522-3535 (2013)] presented a method that used all four channels recorded by one OBS to derive the range and azimuth of fin whale calls. In this work, the detection, classification, and ranging of calls using this four-channel method were further investigated, focusing on methods to increase the accuracy of range estimates to direct path arrivals. Corrections to account for the influences of the sound speed in the water layer and the velocity structure in the top strata of the seabed were considered. The single station method discussed here is best implemented when OBSs have been deployed in deep water on top of seabed strata with low P-wave velocity. These conditions maximize the ability to detect and estimate ranges to fin whale calls.
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机译：海洋中的被动地震监测使用海底地震仪（OBS）的长期部署。 OBS通常记录地震动和压力的三个分量，通常为100Hz。这使OBS成为研究以低于45Hz的频率发声的鳍鲸和蓝鲸的理想工具。 OBS数据在以前的定位鲸鱼呼叫中的应用依赖于单通道分析，而无视水平地震通道所传递的信息。最近，哈里斯，马蒂亚斯，托马斯，哈伍德和盖斯勒[J. co Soc。上午。 134，3522-3535（2013）]提出了一种方法，该方法使用一个OBS记录的所有四个通道来推算长须鲸的鸣叫范围和方位角。在这项工作中，使用这种四通道方法对呼叫的检测，分类和范围进行了进一步的研究，重点是提高范围估计以指导路径到达的准确性的方法。考虑了考虑水层声速和海床顶地层速度结构影响的校正。当OBS已以低P波速度部署在海床地层顶部的深水中时，最好地实现此处讨论的单站方法。这些条件可以最大程度地检测和估计鲸鱼鸣叫的范围。
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