The double seismic zone in downgoing slabs and the viscosity of the mesosphere
The double seismic zone in downgoing slabs and the viscosity of the mesosphere
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下行板片双地震带与中层粘性
DOI：
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发表时间：
1979
期刊：
影响因子：
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通讯作者：
N. Sleep
中科院分区：
文献类型：
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作者：
N. Sleep
在几个岛弧之下的地震带在大约100和200公里深度之间由具有下倾压缩的上部带和具有下倾张力的下部带组成。阿留申弧的几个数值模型进行了计算，以测试的假设，这些双地震带是由于下沉的板在其自身的重量。这种下沉的发生是因为软流层（约100至200公里之间）对板块几乎没有提供支撑或阻力，板块从下面受到更粘的中间层的支撑，从上面受到岩石圈的支撑。中间层的粘度被限制在0.25×1022和0.5×1022 P之间的范围内，注意到板片在较高粘度下主要是向下倾斜的压缩，而在较低粘度下主要是向下倾斜的张力。板块和板块与岛弧之间断层面的偏应力约为200-300巴（以剪应力表示）。根据观测到的海沟深度和重力异常对模型进行了校准。
The seismic zone beneath several island arcs between about 100 and 200 km depth consists of an upper zone having down-dip compression and a lower zone having down-dip tension. Several numerical models of the Aleutian arc were computed to test the hypothesis that these double seismic zones are due to sagging of the slab under its own weight. This sagging occurs because the asthenosphere (between about 100 and 200 km) provides little support or resistance to the slab, which is supported from below by the more viscous mesosphere and from above by the lithosphere. The viscosity of the mesosphere was constrained to the interval between 0.25×1022 and 0.5×1022 P by noting that the slab would have mainly down-dip compression at higher viscosities and mainly down-dip tension at lower viscosities. The deviatoric stress in the slab and the fault plane between the slab and the island arc is about 200–300 bars (expressed as shear stress). The models were calibrated to the observed depth and gravity anomalies in the trench.