Multiscale seismic imaging of the San-Andreas-Fault system

SAFOD（San-Andreas-Fault-Observatory-at-Depth）项目的主要目标是回答有关控制板块边界断层内断层和地震生成的物理和化学过程的基本问题。在这方面，最近通过获取和分析各种地球科学数据集取得了重大进展。 我们建议通过不同尺度的地震成像构建详细的地壳断面，以促进这一认识。一方面，我们希望使用创新的地震成像技术（Fresnel体积偏移）重新处理现有的工业地震反射数据和USGS地震折射数据（“SJ 6”断面），以便绘制和分析其大规模构造清单和构造环境。我们希望这样的再处理将解决特别是大规模的深度结构和深根的圣安德烈亚斯断层系统，这还没有实现使用最近的地震数据集。另一方面，我们希望使用反射地震技术处理SAFOD钻孔内记录的微地震数据，这些数据照亮了断层系统的附近分支，以便揭示钻孔附近的精细断层结构。这些成像结果可以直接用作地震调查的校准工具，以及在SAFOD正在进行的钻探阶段进行的钻孔研究。这种多尺度方法将提供全面的地震图像，可用作地下环境的深刻表征的基础，并可决定性地有助于了解这一主要板块边界断层系统的孕震过程。

The main objective of project SAFOD (San-Andreas-Fault-Observatory-at-Depth) is to answer fundamental questions about the physical and chemical processes controlling faulting and earthquake generation within a major plate-bounding fault. In that respect significant progress has been achieved recently by acquiring and analyzing various geoscientific data sets. We propose to contribute to this understanding by constructing detailed crustal transects across this plate boundary zone from seismic imaging on different scales. On one hand we want to reprocess existing industry seismic reflection data and USGS seismic refraction data ("SJ6" transect) using innovative seismic imaging techniques (Fresnel-Volume-Migration) in order to map and to analyze its large-scale structural inventory and tectonic environment. We expect that such a reprocessing will resolve in particular the large-scale depth structure and the deep roots of the San-Andreas-Fault system, which has not yet been achieved using recent seismic data sets. On the other hand we want to process microseismic data recorded within the SAFOD borehole, which have illuminated nearby branches of the fault system, using reflection seismic techniques in order to reveal the fine-scale fault structure in the close vicinity of the borehole. These imaging results can be directly used as a calibration tool for seismological investigations as well as borehole studies during the ongoing drilling phase at SAFOD. This multiscale approach will deliver comprehensive seismic images which can be used as a basis for a profound characterization of the subsurface environment and can decisively contribute to the understanding of the seismogenic processes at this major plate bounding fault system.