Collaborative Research: Seismic Investigation of Deep Continental Structure in Tanzania, East Africa

9304555兰斯顿本研究旨在利用PASSCAL台阵的被动震源地震记录和重力数据分析，对坦桑尼亚的地壳和上地幔结构进行研究。古老大陆区域之下厚重的亏损地幔岩石圈的存在构成了大陆深部结构模型的基础。这一模型的一个主要论断是，克拉通核及其岩石圈龙骨是一般可移动且不太稳定的岩石圈中构造稳定的真正孤岛。这项工作将通过检查东非一个活跃构造地区克拉通岩石圈的稳定性来检验这一大陆深部结构模型。东非(坦桑尼亚克拉通)的克拉通岩石圈受到新生代伸展构造作用的影响，这为确定深部克拉通结构是否能够在伸展事件中“幸存”提供了独特的机会，伸展事件对邻近较年轻的岩石圈造成了热和机械破坏。在美国，类似的构造是当前地震活动的场所，这些结果将与发震构造的机制有关。这项研究是国家减少地震灾害计划的一部分。***

9304555 Langston This research is to conduct a study of the crustal and upper mantle structure in Tanzania by means of passive-source seismic recording with the PASSCAL array and by means of analysis of gravity data. The existence of thick, depleted mantle lithosphere beneath ancient continental regions forms the basis of the model for deep continental structure. A principal assertion of this model is that cratonic nuclei with their lithospheric keels are true islands of tectonic stability within a generally mobile and less stable lithosphere. This work will test this model of deep continental structure by examining the stability of cratonic lithosphere in an area of active tectonism, East Africa. The cratonic lithosphere in East Africa (the Tanzania Craton) has been subjected to Cenozoic extensional tectonism, providing a unique opportunity to determine if deep cratonic structure can "survive" an extensional event which has thermally and mechanically disrupted adjacent younger lithosphere. Similar structures in the U.S. are the sites of current seismic activity and these results will bear on the mechanism of the earthquake generating structure. This research is a component of the National Earthquake Hazard Reduction Program. ***