Collaborative Research: The context for rifting in East Africa - melt distribution and lithospheric removal imaged from axis to flank

大陆裂谷是板块构造旋回的一个基本组成部分，是地热和矿产资源、地震和火山灾害以及地球物理研究的中心。世界范围内裂谷带之间的巨大差异表明，大陆的分裂是由构造力和地质特征的复杂相互作用决定的。因此，了解裂谷系统的完整背景至关重要，从容纳火山和地震的高度延伸的裂谷中心到裂谷的侧翼，那里的延伸刚刚开始，前裂谷结构仍然很明显。东非裂谷的埃塞俄比亚主裂谷段可能是世界上最具标志性的大陆裂谷。新的成像技术将应用于最近获得的跨越该裂谷的地震数据，以揭示该裂谷的三维内部结构，并揭示该裂谷和世界各地其他裂谷的关键地质过程。该项目涉及与埃塞俄比亚科学家的合作，并为地球科学领域代表性不足的早期职业研究人员提供职业机会。详细成像的内部结构的整个裂谷系统，从侧面到轴，可以阐明的力学，控制和时间依赖性的伸展过程中的主要埃塞俄比亚裂谷。最近获得的数据，从一个大口径宽带地震阵列是至关重要的采样前断裂结构，可能控制裂谷动力学，以及图像的地球动力学关键的过渡带之间的裂谷轴和侧翼。 我们的层析成像技术需要同时反演P和S接收器功能与瑞利波相速度在贝叶斯框架内，这种方法非常适合捕捉岩性/地震不连续性，熔体的存在下，和复杂的3-D裂谷结构。各向异性体波反演和分裂的研究将有助于限制熔体的轨迹，以及时间积分的应变历史的这个裂缝。该项目利用该地区以前一些项目的地震数据，结合多个部署的优势，以实现对天气的了解。 与埃塞俄比亚科学家的合作和支持代表性不足的研究人员的早期职业生涯是该项目更广泛的影响之一。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Continental rifting is a fundamental part of the plate tectonic cycle, and lies at the nexus of geothermal and mineral resources, seismic and volcanic hazards, and geophysical research. Substantial variation between rift zones worldwide indicates that continental breakup is dictated by a complex interplay of tectonic forces and geologic characteristics. Therefore, it is critical to understand the full context for a rifting system, from the highly extended rift center that houses volcanoes and earthquakes to the flanks of the rift, where extension is just beginning and pre-rift structures are still evident. The Main Ethiopian Rift segment of the East Africa rift is perhaps the world's most iconic continental rift. New imaging techniques will be applied to recently acquired seismic data spanning this rift to reveal the 3-D internal structure of this rift and shed light on key geologic processes in this and other rifts around the world. This project involves collaboration with scientists from Ethiopia and provides career opportunities for early career researchers under-represented in the Earth sciences. Detailed imaging of the internal structure of an entire rift system, from flank to axis, can shed light on the mechanics, controls, and time-dependency of extensional processes in the Main Ethiopian Rift. Recently acquired data from a wide aperture broadband seismic array is critical in sampling pre-rifted structure that may control rift dynamics, as well as to image the geodynamically crucial transitional zone between rift axis and flank. Our tomographic technique entails simultaneous inversion of P and S receiver functions with Rayleigh wave phase velocities within a Bayesian framework; this approach is ideally suited to capture lithologic/seismic discontinuities, the presence of melt, and complex 3-D rift structure. Anisotropic body wave inversions and splitting studies will help constrain the locus of melt as well as the time-integrated strain history of this rift. This project utilizes seismic data from a number of previous projects in the region, combining the strengths of multiple deployments to achieve a synoptic understanding. Collaboration with Ethiopian scientists and supporting the early careers of under-represented researchers are among the broader impacts of this project.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.