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

最上面的大洋地壳(第2A层)的地震速度随着年龄的增加而增加。这种渐进的变化是依赖于年龄的地质过程的证据，可能与地壳形成后不久影响地壳的热液循环和蚀变有关。这一过程的一个重要后果是成矿作用，例如，包括世界上大多数地区的S经济铜矿床。然而，这一过程及其与地震结构的关系仍然知之甚少。解决最上层洋壳的地震结构及其与洋壳地质结构和演化的关系是三十多年来一直存在的问题。钻探(例如，在504现场)和潜水研究(例如，在Blanco断裂带和Hess Deep)都提高了我们对地质结构的了解，但地质结构和地震结构之间的明显相关性未能在很大程度上出现，这在很大程度上是因为地震结构无法分辨，即使是最坚定的努力也是如此。Christeson提出的波形反演法具有解决2A/2B层地震结构的可能性，在经历了几十年的挫折后，在这一领域的研究取得了突破。如果成功，这项技术可以应用于来自不同地区，特别是太平洋地区的大量现有地震数据。这项研究的主要更广泛影响将是将波场反演技术引入海洋地震数据，并对各种问题进行解释。该奖项还将支持一名女性调查员。

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.