Seismic‐acoustic sensing of sea ice wave mechanical properties
Seismic‐acoustic sensing of sea ice wave mechanical properties
复制标题
海冰波力学特性的地震声学传感
DOI：
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复制
发表时间：
1994
期刊：
影响因子：
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通讯作者：
D. Farmer
中科院分区：
文献类型：
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作者：
Yunbo Xie;D. Farmer
Sea ice inhomogeneities can be probed by seismic and acoustic waves. Observations of the seismic-acoustic response of first-year sea ice to artificially generated impacts created by dropping a lead ball from a fixed height show that an ice ridge in the path of a propagating seismic wave dampens the wave. This damping effect is found to be sensitive to the angle of incidence, especially at high frequencies (∼100 Hz). Both the longitudinal (P wave) and horizontally polarized shear (SH) wave speeds are found to be much more variable in the vicinity of the ridge; outside of the ridged area the shear wave speed is relatively uniform, varying by only 13% in contrast to the 27% variability of the P wave speed. The Crary wave, which is a special case of the vertically polarized wave (SV), is most easily induced by seafloor-reflected acoustic waves penetrating the ice at large grazing angles. When an ice sheet is struck with a vertical blow, it radiates sound with a dipole pattern; the radiated frequency also depends on the radiation angle with higher-frequency energy projected preferentially downward. Most of the potential energy resulting from artificial impacts is dissipated through damaging the ice surface, with only a small fraction being converted into acoustic and seismic waves.
