CSEDI Collaborative Research: The Thermal, Petrological, and Seismological Structure of Subducting Oceanic Lithosphere

CSEDI合作研究：俯冲大洋岩石圈的热学、岩石学和地震结构

• 批准号: 9809832
• 负责人: Geoffrey Abers
• 金额: $ 1.73万
• 依托单位: University of Kansas Center for Research Inc
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-07-15 至 1999-10-25
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9809832&HistoricalAwards=false
• 关键词: CSEDI; Collaborative; Research; Thermal; Petrological

9809832AbersThe goal of this project is integration of thermal and kinetic models with seismological data for subduction zones that exhibit seismological evidence for sluggish transformation of basalt and gabbro to eclogite. The PIs begin by producing a kinematic thermal model that yields transient and steady-state thermal structures and the pressure-temperature-time evolution of the subducting slab and overlying mantle wedge. Next, equilibrium and kinetic phase transformation models are used to predict mineral assemblages, densities, and seismic wave speeds. The calculated velocity structure is then evaluated by its ability to predict observed seismic properties of waveform dispersion and converted phase amplitudes. Misfit between the petrologically predicted and the seismologically observed velocity structure is then minimized by iterative repetition. If the assumption is made that high fluid pressures are required for intermediate depth earthquakes, then the loci of dehydration reactions and the resultant volatile flux can also be used to predict hypocenter locations and compared to observed earthquake hypocenters. The resulting integrated model of the thermal, petrological, and seismological properties of subducting slabs will yield further insight into other plate boundary processes such as intermediate-depth earthquakes, arc magmatism, and the recycling of volatiles.

该项目的目标是将热动力学模型与俯冲带的地震数据相结合，这些俯冲带显示了玄武岩和辉长岩向榴辉岩缓慢转变的地震证据。pi首先生成一个运动学热模型，该模型可以得到瞬态和稳态热结构，以及俯冲板块和上覆地幔楔的压力-温度-时间演化。接下来，平衡和动力学相变模型用于预测矿物组合、密度和地震波速度。计算出的速度结构通过其预测波形频散和转换相幅值的观测地震特性的能力进行评价。岩石学预测的速度结构与地震学观测的速度结构之间的不匹配，然后通过迭代重复最小化。如果假定中深度地震需要较高的流体压力，那么脱水反应的位置和由此产生的挥发通量也可以用来预测震源位置，并与观测到的震源进行比较。由此产生的俯冲板块的热、岩石学和地震学性质的综合模型将进一步深入了解其他板块边界过程，如中深度地震、弧岩浆活动和挥性物的再循环。