Infragravity waves and horizontal seafloor compliance
Infragravity waves and horizontal seafloor compliance
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DOI：
10.1002/2015jb012511
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发表时间：
2016-01-01
影响因子：
3.9
通讯作者：
Laske, Gabi
中科院分区：
文献类型：
--
作者：
Doran, Adrian K.;Laske, Gabi
我们报告了由次重力（IG）波引起的水平海底顺应性的第一次一致观察。长周期IG海浪在海底压力和垂直形变谱中表现为广泛的主导特征，但由于低信号电平和长周期高电流引起的倾斜噪声，传统海底地震仪（OBS）的水平分量很少（如果有的话）被识别出来。我们研究了两个海底地震仪台站：加利福尼亚州近海的蒙特雷海底宽带站点和夏威夷附近的海洋地震台网（OSN）试点站点OSN1B。我们使用附近的气象浮标来研究亚重力波的存在与环境条件之间的关系。我们发现有力的证据表明，次引力波的产生主要局限于近岸环境。通过检查通过的IG波的方向性作为频率的函数，可以发现额外的IG源信息，我们使用压力和两个水平分量之间的相干性来分析。最后，我们评估了关节垂直和水平顺应性反演的意义。
We report the first consistent observation of horizontal seafloor compliance induced by infragravity (IG) waves. Long-period IG ocean waves manifest themselves as broad, dominant features in ocean bottom pressure and vertical deformation spectra, but signals are rarely (if ever) identified on the horizontal components of traditional ocean bottom seismometers (OBS) due to low signal level and high current-induced tilt noise at long periods. We examine two OBS stations with shallow-buried seismometers: the Monterey Ocean Bottom Broadband site offshore California and the Ocean Seismic Network (OSN) pilot site OSN1B near Hawaii. We use nearby weather buoys to investigate the relationship between the presence of infragravity waves and environmental conditions. We find strong evidence that infragravity wave generation is primarily confined to the near-coastal environment. Additional IG source information is found by examining the directionality of passing IG waves as a function of frequency, which we analyze using the coherence between pressure and the two horizontal components. Finally, we evaluate the implications for a joint vertical and horizontal compliance inversion.