Imaging of the Hellenic subduction zone with S-P converted phases

使用 S-P 转换相对希腊俯冲带进行成像

• 批准号: 5411304
• 负责人: Professor Dr. Rainer Kind
• 金额: --
• 依托单位: Helmholtz-Zentrum Potsdam - Deutsches GeoForschungsZentrum (GFZ)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2003
• 资助国家: 德国
• 起止时间: 2002-12-31 至 2005-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/5411304?language=en
• 关键词: Imaging; Hellenic; subduction; zone; converted

The seismological images of the Hellenic subduction zone derived so far with P-wave receiver functions have large gaps in the Sea of Crete and the central Aegean. The crustal structure in areas not covered by P-wave receiver functions can be probed with S-P converted waves from both nearby local earthquakes and distant earthquakes. It can be shown that the conversion points of S-P converted waves lie up to 70-80 km off the stations for conversion depths of 25 km because the upgoing converted phases are refracted away from the vertical at seismic boundaries. This offers an opportunity to sample seismic boundaries in sea areas with data from nearby land stations at low costs as compared to the deployment of ocean-bottom seismographs for the study of steeply propagating P-S phases that are converted at the same point of a seismic boundary. We will use existing station data from intermediate-depth local and shallow distant earthquakes for a comprehensive study of S-P converted phases that appear as precursors to S and SKS and that offer an alternative method to infer depths to, and velocity contrasts across seismic boundaries in the area of the Sea of Crete and the central Aegean. This will complement our P-S receiver function images of the Hellenic subduction zone and provide, on a regional scale, a complete structural frame for the discussed drilling site in central Crete.

希腊俯冲带的地震学图像与P-波接收器功能推导到目前为止有很大的差距，在克里特海和爱琴海中部。利用近震和远震的S-P转换波可以探测P波接收函数未覆盖地区的地壳结构。结果表明，转换深度为25 km时，转换波转换点距台站70-80 km，这是因为转换波上行相位在地震边界处发生折射而偏离垂线。与部署海底地震仪研究在地震边界的同一点转换的急剧传播的P-S相位相比，这提供了一个机会，利用附近陆地台站的数据以低成本对海域的地震边界进行采样。我们将使用现有的站数据从中深度的本地和浅远地震的综合研究的S-P转换阶段出现的前兆S和SKS，并提供了一种替代方法来推断深度，和速度对比地震边界在该地区的克里特海和爱琴海中部。这将补充我们的希腊俯冲带的P-S接收器功能图像，并在区域范围内为所讨论的克里特岛中部钻探现场提供完整的结构框架。