Broadband Seismological Investigations of Earth Structure and Earthquake Sources

地球结构和震源的宽带地震研究

• 批准号: 0635570
• 负责人: Thorne Lay
• 金额: $ 52.38万
• 依托单位: University of California-Santa Cruz
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-01-01 至 2012-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0635570&HistoricalAwards=false
• 关键词: Broadband; Seismological; Investigations; Earth; Structure

This is a four-year project supporting the seismological research program conducted by Thorne Lay at the University of California, Santa Cruz. The unifying theme of the research effort is the use of broadband digital seismic data to address fundamental questions about earth structure and earthquake rupture processes. The research is focused on the following areas: (1) seismic wave stacking and migration is being used to image lowermost mantle structure, testing the hypothesis that the post-perovskite phase transition occurs near the top of the D" region, and seeking evidence of a deeper reverse transformation to perovskite above the core-mantle boundary that can constrain thermal gradients in the CMB boundary layer; (2) analysis of large data sets to separate source, receiver and deep propagation complexity is being pursued, seeking to better understand near-source (slab) contributions to waveform complexity and shear wave splitting; (3) stacking and migration of seismograms from deep focus earthquakes is being performed to develop images of upper mantle reflectivity in the vicinity of subduction zones; and (4) analysis of moderate-size earthquake source properties along the Sumatra-Andaman rupture zone and other regions of oblique subduction will be conducted to assess variations in frictional properties. Current advances associated with this research include the first direct determination of heat flux through the core-mantle boundary based on seismological and mineral physics constraints, detection of strong scattering in localized patches at the core-mantle boundary, and three-dimensional imaging of multiple seismic discontinuities in the upper mantle beneath Tonga. This overall research effort involves the PI and two graduate students, with continuing collaborations with colleagues at other institutions. We anticipate continued progress in characterizing dynamical processes associated with the Earth's major boundary layers near the surface and near the core-mantle boundary.

这是一个为期四年的项目，支持索恩·莱（Thorne Lay）在加利福尼亚大学圣克鲁斯分校（Santa Cruz）进行的地震研究计划。 研究工作的统一主题是使用宽带数字地震数据来解决有关地球结构和地震破裂过程的基本问题。 The research is focused on the following areas: (1) seismic wave stacking and migration is being used to image lowermost mantle structure, testing the hypothesis that the post-perovskite phase transition occurs near the top of the D" region, and seeking evidence of a deeper reverse transformation to perovskite above the core-mantle boundary that can constrain thermal gradients in the CMB boundary layer; (2) analysis of large data sets to separate source,接收器和深度传播的复杂性正在追求，寻求更好地理解近源（平板）对波形复杂性和剪切波分裂的贡献；将进行倾斜俯冲区以评估摩擦特性的变化。与这项研究相关的当前进展包括基于地震和矿物质物理学约束的核心透过边界的热通量首次直接确定，在核心掩体边界处的局部斑块中的强散射检测以及对汤加汤加下层层层的多个地震不连续性的三维成像的检测。 这项整体研究工作涉及PI和两名研究生，并与其他机构的同事们继续合作。 我们预计，在表征与地面附近和核心掩体边界附近的地球主要边界层相关的动力学过程方面会持续进展。