Short-Period and Broadband Seismic Investigation of the Core-Mantle Boundary and D"

核幔边界短周期宽带地震研究及D"

• 批准号: 9814811
• 负责人: Justin Revenaugh
• 金额: $ 9.44万
• 依托单位: University of California-Santa Cruz
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-03-01 至 2004-02-29
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9814811&HistoricalAwards=false
• 关键词: Short; Period; Broadband; Seismic; Investigation

9814811RevenaughThis research involves the mapping of a feature just above the core-mantle boundary referred to as the ULVZ (Ultra-Low Velocity Zone). It is a thin layer (less than 40 km thick) characterized by greatly depressed compressional and shear velocities indicating that it is probably partially molten and possibly chemically differentiated from the overlying mantle. Inferred properties of the ULVZ make it an efficient conveyer of heat from the core, a shaper of the geodynamo, and a potential storehouse for deep mantle volatiles. Correlation of core-mantle boundary ULVZ patches with hotspot volcanism at the earth's surface suggests a link to plume genesis, specifically that instability within or on top of the layer may orchestrate heat flow from the deep mantle. To date, 44% of the core-mantle boundary has been probed for the presence or absence of a detectable ULVZ. 25% of the sampled core-mantle boundary is overlain by an ULVZ. This work involves extension of coverage to new areas and more detailed investigation of previously covered areas to refine seismic parameters that will be useful to the mineral physics and mantle dynamics scientists.

9814811Revenaugh 这项研究涉及绘制核幔边界上方的特征（称为 ULVZ（超低速区））。 它是一个薄层（厚度小于 40 公里），其特征是压缩速度和剪切速度大大降低，表明它可能部分熔融，并且可能与上覆地幔发生化学差异。 ULVZ 的推断特性使其成为地核热量的有效输送者、地球发电机的塑造者以及深部地幔挥发物的潜在仓库。 地核-地幔边界 ULVZ 斑块与地球表面热点火山活动的相关性表明与地幔柱成因有关，特别是地层内部或顶部的不稳定性可能会协调来自地幔深处的热流。 迄今为止，已对 44% 的核幔边界进行了探测，以确定是否存在可检测的 ULVZ。 25% 的采样核幔边界被 ULVZ 覆盖。 这项工作涉及将覆盖范围扩展到新区域，并对先前覆盖的区域进行更详细的调查，以细化对矿物物理学和地幔动力学科学家有用的地震参数。