Collaborative Research: High Resolution Imaging of Deep Mantle Structure Using USArray Data

合作研究：使用 USArray 数据对深部地幔结构进行高分辨率成像

• 批准号: 0453884
• 负责人: Thorne Lay
• 金额: --
• 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: 2005
• 资助国家: 美国
• 起止时间: 2005-08-01 至 2010-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0453884&HistoricalAwards=false
• 关键词: Collaborative; Research; Resolution; Imaging; Deep

Title of Project: Collaborative Research: High Resolution Imaging of Deep Mantle Structure Using USArray DataPrincipal Investigators: Thorne Lay, Professor of Earth Sciences, UCSC Ed Garnero, Associate Professor of Geological Sciences, ASUThis project utilizes USArray Transportable Array (TA) and Backbone Array data in high-resolution seismic wave imaging of deep mantle structure. The research plan is designed to scale naturally with the progressive deployment of TA stations in the western U.S, building upon initial results obtained using California regional network data. We are analyzing teleseismic earthquake waves that traverse the deep mantle in three subregions: beneath the southern U.S.-Gulf of Mexico-Central America-Caribbean, under the Central Pacific, and beneath Alaska and northern North America. Seismic methodologies that exploit the relatively dense 70-km station spacing provided by the TA data are being applied. Double-array waveform stacking, Kirchhoff scattering migration in 3D tomographic models, shear-wave splitting analysis allowing for azimuthal anisotropy, and finite frequency tomographic arrival time inversion procedures are the primary methods being applied to broadband P and S waveforms. When the initial TA deployment is completed, it will enable 5-fold increase in deep mantle spatial sampling relative to recently developed localized high resolution models for beneath the Cocos Plate and regional framework structures that we have developed. Particular effort is being focused on the mid- and deep mantle beneath Central America and the Gulf of Mexico, where there is evidence in tomographic models for tabular high velocity structures extending through the lower mantle and spreading broadly in the D" Region, possibly associated with the Farallon slab and with the long history of subduction beneath North America. The velocity gradients, structural continuity, structural fabric, and spatial extent of the deep mantle structure is being examined using arrival time analysis and migration methods, with 2D and 3D synthetic modeling being used to quantify structures and to verify the reliability of the imaging procedures. Corresponding structure beneath the subduction zone under Alaska is being analyzed, and these two convergent zone regions are being compared to the isolated structure under the Central Pacific. We are assessing contributions to deep mantle structure from slab material, a post-perovskite phase transition, deep mantle dynamic flow, and partial melting. These analyses will be closely coordinated with Earthscope investigations of shallow mantle structure, incorporating corrections based on models found by others for receiver structure, lithospheric anisotropy, and upper mantle travel time variations. Our goal is to exploit USArray data to make breakthrough advances in understanding of deep mantle structure and its relationship to mid- and upper-mantle flow associated with the westward movement of the North American continent.

Title of Project: Collaborative Research: High Resolution Imaging of Deep Mantle Structure Using USArray DataPrincipal Investigators: Thorne Lay, Professor of Earth Sciences, UCSC Ed Garnero, Associate Professor of Geological Sciences, ASUThis project utilizes USArray Transportable Array (TA) and Backbone Array data in high-resolution seismic wave imaging of deep mantle structure. 该研究计划旨在随着使用加利福尼亚州区域网络数据获得的初步结果的基础，旨在随着西部西部的TA站进行性部署而自然扩展。 我们正在分析远程震荡的地震浪潮，这些浪潮穿越了三个小区域的深陆壁：在墨西哥中央西部美国 - 加利福尼亚南部，中部太平洋下，阿拉斯加和北美北部的下方。 利用TA数据提供的相对密集的70公里站间距的地震方法正在应用。 双阵列波形堆叠，3D断层扫描模型中的Kirchhoff散射迁移，剪切波分裂分析允许方位角各向异性以及有限的频率层析成像到达时间倒置过程，是应用于宽带P和S波形的主要方法。 当最初的TA部署完成后，相对于最近开发的Cocos Plate和我们开发的区域框架结构的最近开发的局部高分辨率模型，它将使深幔空间采样的深度空间采样增加5倍。 特定的努力集中在中美洲和墨西哥湾的中间和深地幔上，在层状模型中，有证据表明表格高速延伸的高速结构延伸到较低的地幔，并在D“地区广泛传播，可能与Farallon平板和Farallon Slab和Farallon Slab以及北部北部的较长型结构及其结构层面的长期结构，结构上的结构及其结构的较长范围。正在使用到达时间分析和迁移方法检查结构，并使用2D和3D合成模型来量化结构，并验证在阿拉斯加下方的俯冲区域的可靠性。过渡，深层地幔动态流和部分熔化。这些分析将与浅层套结构的Earthscope研究密切协调，并根据其他人发现的接收器结构，岩石圈各向异性和上地幔旅行时间变化的模型结合了校正。 我们的目标是利用USARRAY数据，以在理解深层地幔结构及其与北美大陆向西运动相关的中层和上层流量的关系方面取得突破。