Acoustic Waves in Ocean Sediments
Acoustic Waves in Ocean Sediments
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DOI：
10.1190/1.1440741
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发表时间：
1977-06
期刊：
影响因子：
3.3
通讯作者：
R. Stoll
中科院分区：
文献类型：
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作者：
R. Stoll
松散沉积物的声学模型被用来研究海洋沉积物中的速度、衰减和反射。该模型根据孔隙度、颗粒大小、渗透率和有效应力等物理参数来预测衰减和波速。模型中包含了两种能量损失机制；一种考虑了骨架框架中的颗粒间损失，另一种考虑了孔隙水相对于框架运动时的粘性损失。因此，在某些沉积物中，如沙子和淤泥，衰减的变化方式与通常几乎普遍假设的对频率一次功率的依赖完全不同。此外，水和沉积物之间或沉积物之间的边界上的反射和折射波的幅度与频率有关。在这种边界附近，由于产生了具有极高密度的第二类膨胀波，可能会损失大量的能量。
An acoustic model for unconsolidated sediments is used to study velocity, attenuation, and reflection in ocean sediments. The model predicts attenuation and wave velocity on the basis of physical parameters such as porosity, grain size, permeability, and effective stress. Two mechanisms for energy loss are included in the model; one accounts for intergranular losses in the skeletal frame and the other for viscous losses in the porewater as it moves relative to the frame. As a result, in certain sediments such as sands and silts, attenuation is found to vary in a manner quite different from the usual dependency on the first power of frequency that is almost universally assumed. Furthermore, the amplitudes of reflected and refracted waves at boundaries between water and sediment or between sediment layers become frequency dependent. In the immediate vicinity of such boundaries, a significant amount of energy may be lost owing to the generation of a second kind of dilatational wave with extremely high attenu...