论文部分内容阅读
用径向分层的地球模型和可靠的矩张量解,估计了最近20年中大地震对极移的贡献。和以前仅考虑地球弹性响应引起地震矩释放的分析不同,我们考虑了地幔流变,以及由全球地震活动驱动的与时间相关的震后惯量的改变。我们证明,最近20年中,全球地震活动没有明显改变地球自转的参数。然而,我们发现对于最新研究震后应力扩散中提出的软流层粘度值,即便在10年尺度上,地幔的滞后驰豫也可把平均极移率增大1.2～1.7倍(取决于软流层宽度)。
Using radial layered earth model and reliable moment tensor solution, the contribution of large earthquakes in the recent 20 years to polar motion is estimated. In contrast to the previous analysis that considered the earthquakes momentarily released by the Earth’s elastic response, we considered changes in mantle rheology and time-related post-earthquake inertia driven by global seismicity. We show that in the last 20 years, global seismicity has not significantly changed the parameters of Earth’s rotation. However, we found that the lag relaxation of the mantle can also increase the average rate of displacement by 1.2 to 1.7 times, even on a 10-year scale, depending on the asthenospheric viscosity proposed in the latest study of stress dispersion Layer width).