Study on Temporal Variations of S Wave Anisotropy in the Mantle.

地幔S波各向异性随时间变化的研究。

• 批准号: 10640405
• 负责人: FURUMOTO Muneyoshi
• 金额: $ 2.18万
• 依托单位: Kanazawa University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10640405/
• 关键词: S Wave Anisotropy; D" Layer; Core-Mantle-Boundary; Temporal variation; マントル; 異方性

In order to study the possibility that features of the S wave polarization anisotropy in the D" layer change quickly, we analyze the splitting of ScS waves which are radiated from deep earthquakes around Japan and recorded stations in Japan. The used seismological records are those obtained by Japan Meteorological Agency and several universities. Including results reported previously by us and other researchers, we obtain 35 azimuths of the anisotropic pricipal axes for the last three decades. The temporal variation of the azimuths shows that the directions of pricipal axes do not change with time at least in an order of ten years. However, the data suggests that there is a possibility of the temporal variation of the axis direction in a longer period.

为了研究D”层S波极化各向异性特征快速变化的可能性，我们分析了日本周边深层地震和日本记录台站辐射的sc波的分裂。使用的地震记录是日本气象厅和几所大学获得的地震记录。包括我们和其他研究人员之前报道的结果，我们得到了近30年来各向异性主轴的35个方位角。方位角的时间变化表明，主轴方向至少在十年的量级上不随时间变化。然而，这些数据表明，在较长的时期内，轴向存在时间变化的可能性。