SGER: Seismic Waveform Inversion Study of the Layer 2A/2B Boundary in Young Oceanic Crust

最上层洋壳（2A层）的地震速度随年龄增加而增加。这种渐进的变化是年龄相关的地质过程的证据，可能与热液循环和蚀变有关，这些热液循环和蚀变在地壳形成后不久就影响了地壳。这一过程的一个重要后果是矿化，包括，例如，世界上大部分地区？的经济铜矿床。然而，这个过程及其与地震结构的关系仍然知之甚少。30多年来，解决最上层洋壳的地震结构及其与地质结构和洋壳演化的关系一直是一个持续存在的问题。这两种钻孔（例如，在504站点）和潜水研究（例如，在布兰科断裂带和赫斯深部的地震构造的研究）提高了我们对地质构造的认识，但地质构造和地震构造之间的明确相关性在很大程度上未能出现，因为地震构造的分辨率难以确定，即使是最坚定的努力也无法确定。Christeson提出的波形反演方法有可能解决2A/2B层的地震结构，从而在几十年的挫折后在这一领域的研究中取得突破。如果成功的话，这项技术可以应用于来自不同地点，特别是太平洋地区的大量现有地震数据。该SGER的主要广泛影响将是将波场反演技术引入海洋地震数据及其对各种问题的解释。该奖项还将资助一名女调查员。

Seismic velocities in the uppermost oceanic crust (Layer 2A) increase with age. This progressive change is evidence of age dependent geologic processes, probably related to hydrothermal circulation and alteration that affects the crust soon after its formation. One significant consequence of this process is mineralization, including, for example, most of the world?s economic copper deposits. However, the process and its relationship to the seismic structure remain poorly understood. Resolving the seismic structure of the uppermost oceanic crust and its relationship to the geologic structure and evolution of the oceanic crust has been a persistent problem for more than three decades. Both drilling (e.g., at Site 504) and submersible studies (e.g., at Blanco Fracture Zone and Hess Deep) have improved our understanding of the geologic structure, but a clear correlation between the geologic structure and the seismic structure has failed to emerge in large part because the seismic structure has defied resolution, even by the most determined efforts. The waveform inversion approach proposed by Christeson holds the possibility of resolving the Layer 2A/2B seismic structure, and hence producing a breakthrough in this area of study after decades of frustration. If successful, the technique can be applied to a great deal of existing seismic data from a variety of localities, particularly in the Pacific. The primary broader impact of this SGER will be the introduction of the wave-field inversion technique to marine seismic data and its interpretation to a variety of problems. This award will also support a female investigator.