Analysis of Regional Phase Data from USArray

USArray 区域相位数据分析

• 批准号: 0950391
• 负责人: Peter Shearer
• 金额: $ 25.11万
• 依托单位: University of California-San Diego Scripps Inst of Oceanography
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-05-01 至 2014-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0950391&HistoricalAwards=false
• 关键词: Analysis; Regional; Phase; Data; USArray

Scientists from Scripps Institution of Oceanography (SIO), University of California, San Diego (UCSD), are analyzing seismograms from the USArray project (part of NSF's Earthscope program) from earthquakes and explosions recorded at regional distances (200 to 2000 km). These data provide new constraints on crust and upper-mantle structure in the western United States. In particular, researchers are studying the upper-mantle seismic phases Pn and Sn and the crustal phases Pg and Lg. The project involves performing Pn tomography using USArray phase picks, producing maps of crustal thickness and both isotropic and anisotropic variations in uppermost mantle P velocity that agree with previous results in their large-scale features but show more detail in many regions. Preliminary results suggest that Sn data in USArray are of comparable quality, enabling joint Pn/Sn inversions to constrain uppermost mantle structure and anisotropy. In many cases, crustal phases such as Lg can be observed to long distances in the USArray dataset, making possible a comprehensive analysis of Pg and Lg times and amplitudes to resolve lower crustal velocities and attenuation. These results complement shear-wave splitting and surface- and body-wave tomography studies by providing superior resolution for structures at lower crustal and uppermost mantle depths. This research will lead to improved models of crust and upper-mantle structure in the western United States, which will be of interest to the geology, tectonics, and geodynamics communities. The project supports the educational program at SIO and UCSD by providing funds for a graduate student. Results will be widely disseminated through publications, conference presentations, and material provided to SIO's education and outreach programs.

来自加州大学圣地亚哥分校斯克里普斯海洋学研究所（SIO）的科学家们正在分析USAray项目（NSF Earthscope计划的一部分）的地震图，这些地震图来自区域距离（200至2000公里）记录的地震和爆炸。 这些数据为美国西部的地壳和上地幔结构提供了新的约束。 特别是，研究人员正在研究上地幔地震相位Pn和Sn以及地壳相位Pg和Lg。该项目涉及使用USAray相位拾取进行Pn层析成像，制作地壳厚度以及上地幔P速度各向同性和各向异性变化的地图，这些地图与以前的结果在大尺度特征上一致，但在许多地区显示出更多细节。 初步结果表明，在USAray的Sn数据的质量相当，使联合Pn/Sn反演约束上地幔结构和各向异性。 在许多情况下，可以在USArray数据集中长距离观察地壳相位，如Lg，从而可以对Pg和Lg时间和振幅进行全面分析，以解决较低的地壳速度和衰减。 这些结果补充了剪切波分裂和表面波和体波层析成像研究提供上级分辨率的结构在地壳下部和地幔上部的深度。 这项研究将导致美国西部地壳和上地幔结构的改进模型，这将是地质学，构造学和地球动力学社区的兴趣。该项目通过为研究生提供资金来支持SIO和UCSD的教育计划。研究结果将通过出版物、会议报告和提供给SIO教育和外联方案的材料广泛传播。