Direct Imaging of Crust and Upper Mantle Structure with Broadband Seismic Arrays

建议摘要EAR0106062(PH#34X)标题：用宽带地震阵列直接成像地壳和上地幔结构PI：Gary L.Pavlis，印第安纳大学，布鲁明顿我们开发了一种新的P到S转换相直接成像的技术。它建立在石油和天然气行业使用的成像概念的基础上，以直接对反向散射(反射)地震波进行成像，但我们使用由远距离地震产生的正向散射P到S转换，而不是由人工震源产生的后向散射波。这使我们能够直接处理远距离地震的原始记录，以产生地震阵列下P到S散射势的图像。所使用的数学模型是一种适合于这种波相互作用的逆散射形式。到目前为止，该技术的应用揭示了以前未见过的倾斜边界的存在，这些边界与大陆内的古代缝合带重合。这项技术的现有应用仅限于2D切片。拟议的项目将扩展这项技术的能力，以产生宽带阵列下P到S转换结构的3D图像。这项技术将应用于最近在中亚天山完成的阵列实验数据，以解决大陆-大陆碰撞带地幔和地壳过程关系的基本问题。我们还建议将这种方法应用于南加州可用的新的、密集的宽带阵列数据。这可能为了解与圣安德烈亚斯断裂系统有关的上地幔流动的性质提供新的见解。

Abstract for proposal EAR0106062 (PH # 34x)Title: Direct Imaging of Crust and Upper Mantle Structure with Broadband Seismic ArraysPI's: Gary L. Pavlis, Indiana University, Bloomington We have developed a new technology for direct imaging of P to S converted phases. It builds on imaging concepts used in the oil and gas industry to directly image backscattered (reflected) seismic waves, but we utilize forward scattered P to S conversions produced by distant earthquakes instead of backscattered waves generated by artificial sources. This allows us to directly manipulate raw recordings of distant earthquakes to produce an image of P to S scattering potential underneath a seismic array. The mathematical model used is a form of inverse scattering appropriate for this type of wave interaction. Applications of the technique to date have revealed the presence of previously unseen dipping boundaries that coincide with ancient suture zones within the continents. Existing applications of the technique have been limited to 2D slices. The proposed project would extend the capabilities of this technique to produce 3D images of P to S conversion structure beneath broadband arrays. The technique will be applied to data from the recently completed array experiment in the Tien Shan of central Asia to address fundamental issues about the relation of mantle and crustal processes in continent-continent collision zones. We also propose to apply this approach to new, dense broadband array data available in southern California. This may provide new insights on the nature of flow in the upper mantle connected with the San Andreas fault system.