Background Love and Rayleigh waves simultaneously generated at the Pacific Ocean floors
Background Love and Rayleigh waves simultaneously generated at the Pacific Ocean floors
复制标题
DOI：
10.1029/2008gl034753
复制
发表时间：
2008-08
影响因子：
5.2
通讯作者：
Kiwamu Nishida;H. Kawakatsu;Y. Fukao;K. Obara
中科院分区：
文献类型：
--
作者：
Kiwamu Nishida;H. Kawakatsu;Y. Fukao;K. Obara
地球的背景自由振荡被称为地球的嗡嗡声，被解释为地球对大气和/或海洋扰动引起的垂直压力载荷的响应。然而，这样的激发机制很难激发Love波。在这里，我们显示了明确的证据，从0.01到0.1赫兹的背景爱波，在日本岛屿的倾斜仪阵列分析的基础上。在整个分析周期内，观测到的Love波动能与Rayleigh波动能一样大。主要的入射方位角与Love波和Rayleigh波相同，最强的方向是沿着海洋-大陆边界，其次是深海海底，最弱的方向是大陆。这些观察结果表明，背景洛夫波和瑞利波主要是由相同的机制，而不是垂直压力加载。我们认为，最有可能的激发源是剪切牵引作用在海底地平线上，由于线性地形耦合的亚重力波。
Earth's background free oscillations known as Earth's hum have been interpreted as the Earth response to vertical pressure loads due to atmospheric and/or oceanic disturbances. Such excitation mechanisms, however, can hardly excite Love waves. Here we show clear evidence of background Love waves from 0.01 to 0.1 Hz, based on the array analysis of tiltmeters in the Japanese islands. The observed kinetic energy of Love waves is as large as that of Rayleigh waves through the whole period of analysis. The predominant incident azimuths are common to the Love and Rayleigh waves, the strongest in directions along ocean‐continent borders, next from deep ocean floors and the weakest from continents. These observations indicate that background Love and Rayleigh waves are largely generated by the same mechanisms other than vertical pressure loading. We suggest that the most likely excitation source is shear traction acting on a sea‐bottom horizon due to linear topographic coupling of infragravity waves.