Excitation of earth's incessant free oscillations by Atmosphere-Ocean-Seafloor coupling
Excitation of earth's incessant free oscillations by Atmosphere-Ocean-Seafloor coupling
复制标题
大气-海洋-海底耦合激发地球不断的自由振荡
DOI：
--
复制
发表时间：
2004
期刊：
影响因子：
--
通讯作者：
J. Rhie
中科院分区：
文献类型：
--
作者：
B. Romanowicz;J. Rhie
日本科学家于1998年首次在无明显地震的时段观测了地球连续激发自由振荡的长周期地震图。从那时起，人们的注意力集中在阐明导致它们的物理机制上。记录中剩余的所有小地震的总和不能解释观测到的激发水平。这种机制一定很浅，因为基模似乎是优先被激发的。它表现出季节性变化，在北半球和南半球的冬天达到顶峰。已经提出了涉及大气中湍流运动的随机机制以及世界各地的源的随机分布。连续振荡的另一个潜在激发源在海洋中，但到目前为止，基于长时间序列上信号的频谱或相关性计算的观测没有空间和时间分辨率来定位这些源。
The observation on long period seismograms of continuously excited free oscillations of the Earth was fi rst made by japanese scientists in 1998, during intervals free of signifi cant earthquakes. Since then, attention has focused on elucidating the physical mechanism responsible for them. The sum of all small earthquakes remaining in the records cannot explain the observed level of excitation. The mechanism must be shallow, as fundamental modes appear to be preferentially excited. It shows seasonal variability, with peaks in the northern and southern hemisphere winters. Stochastic mechanisms involving turbulent motion in the atmosphere have been proposed as well as random distribution of sources around the world. An alternative potential source of excitation of the continuous oscillations is in the oceans, but so far the observations, based on the computation of spectra or correlations of signals across long time series, do not have the spacial and temporal resolution to locate these sources.